Stacked lens structure, method of manufacturing the same, and electronic apparatus

ABSTRACT

A deformation of a stacked lens is suppressed. 
     A stacked lens structure has a configuration in which substrates with lenses having a lens disposed on an inner side of a through-hole formed in the substrate are bonded and stacked by direct bonding. The present technique can be applied to a camera module or the like in which a stacked lens structure in which at least three substrates with lenses including first to third substrates with lenses which are substrates with lenses in which a through-hole is formed in the substrate and a lens is formed on an inner side of the through-hole is integrated with a light receiving element, for example.

TECHNICAL FIELD

The present technique relates to a stacked lens structure, a method ofmanufacturing the stacked lens structure, and an electronic apparatus,and more particular, to a stacked lens structure, a method ofmanufacturing the stacked lens structure, and an electronic apparatus,the stacked lens structure being formed by forming lenses on a substratewhich can be used for manufacturing an electronic device such as asemiconductor device or a flat-panel display device and stacking thelenses in a substrate state.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of Japanese Priority PatentApplication JP 2015-152921 filed on Jul. 31, 2015, the entire contentsof which are incorporated herein by reference.

BACKGROUND ART

In a wafer-level lens process in which a plurality of lenses is arrangedin a plane direction of a wafer substrate, it is difficult to obtain theshape accuracy or the position accuracy when the lenses are formed. Inparticular, it is very difficult to perform a process in which wafersubstrates are stacked to manufacture a stacked lens structure, andstacking of three layers or more is not realized in mass productionlevel.

Various techniques related to the wafer-level lens process have beendevised and proposed. For example, PTL 1 proposes a method in which whena lens material is filled into through-holes formed in a substrate toform a lens, the lens material itself is used as an adhesive to stackwafer substrates.

CITATION LIST Patent Literature [PTL 1] JP 2009-279790 A SUMMARY OFINVENTION Technical Problem

However, as disclosed in PTL 1, when the wafer substrates are attachedusing an adhesive resin, a deformation such as a distortion or apositional shift of a stacked lens is likely to occur due to shrinkageand expansion of the resin.

The present technique has been made in view of this situation and isprovided to suppress a deformation of a stacked lens.

Solution to Problem

A stacked lens structure according to a first aspect of the presenttechnique includes a plurality of substrates including a first substratehaving a first through-hole and a second substrate having asecond-through hole; and a plurality of lenses including a first lensdisposed in the first through-hole and a second lens disposed in thesecond through-hole, wherein, the first substrate is directly bonded tothe second substrate.

A method of manufacturing stacked lens structures according to a secondaspect of the present technique includes forming a first substrateincluding a first through-hole with a first lens disposed therein,forming a second substrate including a second through-hole with a secondlens disposed therein, wherein the first substrate is directly bonded tothe second substrate.

An electronic apparatus according to a third aspect of the presenttechnique includes a camera module including a stacked lens structureincluding: a plurality of substrates including a first substrate havinga first through-hole and a second substrate having a second-throughhole; and a plurality of lenses including a first lens disposed in thefirst through-hole and a second lens disposed in the secondthrough-hole, wherein, the first substrate is directly bonded to thesecond substrate.

The stacked lens structure and the electronic apparatus may beindependent components or apparatuses and may be modules incorporatedinto another apparatuses.

Advantageous Effects of Invention

According to the first to fifth aspects of the present technique, it ispossible to reduce a deformation of a stacked lens.

The advantageous effects described herein are not necessarily presentedin a limiting sense, but any one of the advantageous effects disclosedin the present technique may be exhibited.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram illustrating a first embodiment of a camera modulewhich uses a stacked lens structure to which the present technique isapplied.

FIG. 2 is a diagram illustrating a cross-sectional structure of thestacked lens structure disclosed in Patent Literature 1.

FIG. 3 is a diagram illustrating a cross-sectional structure of thestacked lens structure of the camera module illustrated in FIG. 1.

FIG. 4 is a diagram illustrating direct bonding of a substrate withlenses.

FIG. 5 is a diagram illustrating a step of forming the camera moduleillustrated in FIG. 1.

FIG. 6 is a diagram illustrating a step of forming the camera moduleillustrated in FIG. 1.

FIG. 7 is a diagram illustrating another step of forming the cameramodule illustrated in FIG. 1.

FIG. 8 is a diagram illustrating a configuration of a substrate withlenses.

FIG. 9 is a diagram illustrating a second embodiment of a camera modulewhich uses a stacked lens structure to which the present technique isapplied.

FIG. 10 is a diagram illustrating a third embodiment of a camera modulewhich uses a stacked lens structure to which the present technique isapplied.

FIG. 11 is a diagram illustrating a fourth embodiment of a camera modulewhich uses a stacked lens structure to which the present technique isapplied.

FIG. 12 is a diagram illustrating a fifth embodiment of a camera modulewhich uses a stacked lens structure to which the present technique isapplied.

FIG. 13 is a diagram illustrating a detailed configuration of the cameramodule according to the fourth embodiment.

FIG. 14 illustrates a plan view and cross-sectional views of a supportsubstrate and a lens resin portion.

FIG. 15 is a cross-sectional view illustrating a stacked lens structureand a diaphragm plate.

FIG. 16 is a diagram illustrating a sixth embodiment of a camera modulewhich uses a stacked lens structure to which the present technique isapplied.

FIG. 17 is a diagram illustrating a seventh embodiment of a cameramodule which uses a stacked lens structure to which the presenttechnique is applied.

FIG. 18 is a cross-sectional view illustrating a detailed configurationof a substrate with lenses.

FIG. 19 is a diagram illustrating a method of manufacturing thesubstrate with lenses.

FIG. 20 is a diagram illustrating a method of manufacturing thesubstrate with lenses.

FIG. 21 is a diagram illustrating a method of manufacturing thesubstrate with lenses.

FIG. 22 is a diagram illustrating a method of manufacturing thesubstrate with lenses.

FIG. 23 is a diagram illustrating a method of manufacturing thesubstrate with lenses.

FIG. 24 is a diagram illustrating a method of manufacturing thesubstrate with lenses.

FIG. 25 is a diagram illustrating a method of manufacturing thesubstrate with lenses.

FIG. 26 is a diagram illustrating a method of manufacturing thesubstrate with lenses.

FIG. 27 is a diagram illustrating a method of manufacturing thesubstrate with lenses.

FIG. 28 is a diagram illustrating a method of manufacturing thesubstrate with lenses.

FIG. 29 is a diagram illustrating a method of manufacturing thesubstrate with lenses.

FIG. 30 is a diagram illustrating bonding of substrates with lenses in asubstrate state.

FIG. 31 is a diagram illustrating bonding of substrates with lenses in asubstrate state.

FIG. 32 is a diagram illustrating a first stacking method of stackingfive substrates with lenses in a substrate state.

FIG. 33 is a diagram illustrating a second stacking method of stackingfive substrates with lenses in a substrate state.

FIG. 34 is a diagram illustrating an eighth embodiment of a cameramodule which uses a stacked lens structure to which the presenttechnique is applied.

FIG. 35 is a diagram illustrating a ninth embodiment of a camera modulewhich uses a stacked lens structure to which the present technique isapplied.

FIG. 36 is a diagram illustrating a tenth embodiment of a camera modulewhich uses a stacked lens structure to which the present technique isapplied.

FIG. 37 is a diagram illustrating an eleventh embodiment of a cameramodule which uses a stacked lens structure to which the presenttechnique is applied.

FIG. 38 is a cross-sectional view of a wafer-level stacked structure asComparative Structure Example 1.

FIG. 39 is a cross-sectional view of a lens array substrate asComparative Structure Example 2.

FIG. 40 is a diagram illustrating a method of manufacturing the lensarray substrate illustrated in FIG. 39.

FIG. 41 is a cross-sectional view of a lens array substrate asComparative Structure Example 3.

FIG. 42 is a diagram illustrating a method of manufacturing the lensarray substrate illustrated in FIG. 41.

FIG. 43 is a cross-sectional view of a lens array substrate asComparative Structure Example 4.

FIG. 44 is a diagram illustrating a method of manufacturing the lensarray substrate illustrated in FIG. 43.

FIG. 45 is a cross-sectional view of a lens array substrate asComparative Structure Example 5.

FIG. 46 is a diagram illustrating the effects of a resin which forms alens.

FIG. 47 is a diagram illustrating the effects of a resin which forms alens.

FIG. 48 is a diagram schematically illustrating a lens array substrateas Comparative Structure Example 6.

FIG. 49 is a cross-sectional view of a stacked lens structure asComparative Structure Example 7.

FIG. 50 is a diagram illustrating the effects of the stacked lensstructure illustrated in FIG. 49.

FIG. 51 is a cross-sectional view of a stacked lens structure asComparative Structure Example 8.

FIG. 52 is a diagram illustrating the effects of a stacked lensstructure illustrated in FIG. 51.

FIG. 53 is a cross-sectional view of a stacked lens structure whichemploys the present structure.

FIG. 54 is a diagram schematically illustrating the stacked lensstructure illustrated in FIG. 53.

FIG. 55 is a diagram illustrating a first configuration example in whicha diaphragm is added to a cover glass.

FIG. 56 is a diagram for describing a method of manufacturing the coverglass illustrated in FIG. 55.

FIG. 57 is a diagram illustrating a second configuration example inwhich a diaphragm is added to a cover glass.

FIG. 58 is a diagram illustrating a third configuration example in whicha diaphragm is added to a cover glass.

FIG. 59 is a diagram illustrating a configuration example in which anopening itself of a through-hole is configured as a diaphragm mechanism.

FIG. 60 is a diagram for describing wafer-level attachment using metalbonding.

FIG. 61 is a diagram illustrating an example of a substrate with lenseswhich uses a highly-doped substrate.

FIG. 62 is a diagram for describing a method of manufacturing thesubstrate with lenses illustrated in FIG. 61A.

FIG. 63 is a diagram for describing a method of manufacturing thesubstrate with lenses illustrated in FIG. 61B.

FIG. 64 is a diagram illustrating a planar shape of a diaphragm plateincluded in a camera module.

FIG. 65 is a diagram for describing a configuration of a light receivingarea of a camera module.

FIG. 66 is a diagram illustrating a first example of a pixel arrangementin a light receiving area of a camera module.

FIG. 67 is a diagram illustrating a second example of a pixelarrangement in a light receiving area of a camera module.

FIG. 68 is a diagram illustrating a third example of a pixel arrangementin a light receiving area of a camera module.

FIG. 69 is a diagram illustrating a fourth example of a pixelarrangement in a light receiving area of a camera module.

FIG. 70 is a diagram illustrating a modification of the pixelarrangement illustrated in FIG. 66.

FIG. 71 is a diagram illustrating a modification of the pixelarrangement illustrated in FIG. 68.

FIG. 72 is a diagram illustrating a modification of the pixelarrangement illustrated in FIG. 69.

FIG. 73 is a diagram illustrating a fifth example of a pixel arrangementin a light receiving area of a camera module.

FIG. 74 is a diagram illustrating a sixth example of a pixel arrangementin a light receiving area of a camera module.

FIG. 75 is a diagram illustrating a seventh example of a pixelarrangement in a light receiving area of a camera module.

FIG. 76 is a diagram illustrating an eighth example of a pixelarrangement in a light receiving area of a camera module.

FIG. 77 is a diagram illustrating a ninth example of a pixel arrangementin a light receiving area of a camera module.

FIG. 78 is a diagram illustrating a tenth example of a pixel arrangementin a light receiving area of a camera module.

FIG. 79 is a diagram illustrating an eleventh example of a pixelarrangement in a light receiving area of a camera module.

FIG. 80 is a block diagram illustrating a configuration example of animaging apparatus as an electronic apparatus to which the presenttechnique is applied.

FIG. 81 is a block diagram illustrating an example of a schematicconfiguration of an internal information acquisition system.

FIG. 82 is a diagram illustrating a use example of an image sensor.

DESCRIPTION OF EMBODIMENTS

Hereinafter, modes (hereinafter referred to as embodiments) for carryingout the present technique will be described. The description will begiven in the following order:

1. First Embodiment of Camera Module 2. Second Embodiment of CameraModule 3. Third Embodiment of Camera Module 4. Fourth Embodiment ofCamera Module 5. Fifth Embodiment of Camera Module 6. DetailedConfiguration of Camera Module of Fourth Embodiment 7. Sixth Embodimentof Camera Module 8. Seventh Embodiment of Camera Module

9. Detailed Configuration of Substrate with Lenses10. Method of Manufacturing Substrate with Lenses11. Bonding of Substrates with Lenses

12. Eighth and Ninth Embodiments of Camera Module 13. Tenth Embodimentof Camera Module 14. Eleventh Embodiment of Camera Module

15. Advantages of Present Structure compared to Other Structures

16. Various Modifications 17. Pixel Arrangement of Light ReceivingElement and Structure and Use of Diaphragm Plate 18. Example ofApplication to Electronic Apparatus 19. Use Example of Image Sensor 1.First Embodiment of Camera Module

FIGS. 1A and 1B are diagrams illustrating a first embodiment of a cameramodule which uses a stacked lens structure to which the presenttechnique is applied.

FIG. 1A is a schematic diagram illustrating a configuration of a cameramodule 1A as a first embodiment of a camera module 1. FIG. 1B is aschematic cross-sectional view of the camera module 1A.

The camera module 1A includes a stacked lens structure 11 and lightreceiving elements 12. The stacked lens structure 11 includes twentyfive optical units 13 in total, five optical units in vertical andhorizontal directions each. The optical unit 13 is configured to includea plurality of lenses 21 in one optical axis direction. The cameramodule 1A is a multi-ocular camera module having a plurality of opticalunits 13.

The optical axes of the plurality of optical units 13 included in thecamera module 1A are disposed so as to spread toward the outer side ofthe module as illustrated in FIG. 1B. Due to this, it is possible tophotograph a wide-angle image.

Although the stacked lens structure 11 illustrated in FIG. 1B has astructure in which the lenses 21 are stacked in three layers only forthe sake of simplicity, a larger number of lenses 21 may naturally bestacked.

The camera module 1A illustrated in FIGS. 1A and 1B can stitch aplurality of images photographed by the plurality of optical units 13together to create one wide-angle image. In order to stitch theplurality of images together, high accuracy is demanded in the formationand the arrangement of the optical units 13 photographing the images.Moreover, since the optical units 13 particularly on the wide-angle sidehave a small incidence angle of light incident on the lenses 21, highaccuracy is demanded in the positional relation and the arrangement ofthe lenses 21 in the optical unit 13.

FIG. 2 is a diagram illustrating a cross-sectional structure of astacked lens structure which uses a resin-based fixing technique,disclosed in Patent Literature 1.

In a stacked lens structure 500 illustrated in FIG. 2, a resin 513 isused as a unit for fixing substrates 512 each having lenses 511. Theresin 513 is an energy-curable resin such as an UV-curable resin.

Before the substrates 512 are attached together, a layer of the resin513 is formed on an entire surface of the substrate 512. After that, thesubstrates 512 are attached together, and the resin 513 is cured. Inthis way, the attached substrates 512 are fixed together.

However, when the resin 513 is cured, the resin 513 experiences curingshrinkage. In the case of the structure illustrated in FIG. 2, since theresin 513 is cured after the layer of the resin 513 is formed on theentire substrate 512, the amount of displacement of the resin 513increases.

Moreover, even after the stacked lens structure 500 formed by attachingthe substrates 512 together is divided into individual imaging elementsand the imaging elements are combined to form a camera module, thestacked lens structure 500 provided in the camera module has the resin513 entirely between the substrates 512 having lenses 511 as illustratedin FIG. 2. Due to this, when the camera module is mounted into thehousing of a camera and is used actually, the resin between thesubstrates of the stacked lens structure 500 may experience thermalexpansion due to an increase in the temperature caused by the heatgenerated by the apparatus.

FIG. 3 is a diagram illustrating a cross-sectional structure of thestacked lens structure 11 only of the camera module 1A illustrated inFIGS. 1A and 1B.

The stacked lens structure 11 of the camera module 1A is also formed bystacking a plurality of substrates with lenses 41 having the lenses 21.

In the stacked lens structure 11 of the camera module 1A, a fixing unitwhich is completely different from that used in the stacked lensstructure 500 illustrated in FIG. 2 or that disclosed in the related artis used as a unit for fixing the substrates with lenses 41 having thelenses 21 together.

That is, two substrates with lenses 41 to be stacked are directly bondedby a covalent bond between an oxide or nitride-based surface layerformed on the surface of one substrate and an oxide or nitride-basedsurface layer formed on the surface of the other substrate. As aspecific example, as illustrated in FIG. 4A, a silicon oxide film or asilicon nitride film is formed on the surfaces of the two substrateswith lenses 41 to be stacked as a surface layer, and a hydroxyl radicalis combined with the film. After that, the two substrates with lenses 41are attached together and are heated and subjected to dehydrationcondensation. As a result, a silicon-oxygen covalent bond is formedbetween the surface layers of the two substrates with lenses 41. In thisway, the two substrates with lenses 41 are directly bonded. As theresult of condensation, atoms included in the two surface layers maydirectly form a covalent bond.

As another example, as illustrated in FIG. 4B, a silicon nitride film 42is formed on the surfaces of the two substrates with lenses 41 to bestacked as a surface layer, and a hydroxyl radical is combined with thefilm. For example, NH3 may be used during the plasma activation process.After that, the two substrates with lenses 41 are attached together andare heated and subjected to dehydration condensation. As a result, asilicon-nitrogen covalent bond is formed between the surface layers 42of the two substrates with lenses 41. In this way, the two substrateswith lenses 41 are directly bonded. As the result of condensation, atomsincluded in the two surface layers may directly form a covalent bond.

In the present specification, direct bonding means fixing the twosubstrates with lenses 41 by the layer of an inorganic material disposedbetween the two substrates with lenses 41. Alternatively, direct bondingmeans fixing the two substrates with lenses 41 by chemically combiningthe layers of an inorganic material disposed on the surfaces of the twosubstrates with lenses 41. Alternatively, direct bonding means fixingthe two substrates with lenses 41 by forming a dehydrationcondensation-based bond between the layers of an inorganic materialdisposed on the surfaces of the two substrates with lenses 41.Alternatively, direct bonding means fixing the two substrates withlenses 41 by forming an oxygen-based covalent bond between the layers ofan inorganic material disposed on the surfaces of the two substrateswith lenses 41 or a covalent bond between atoms included in the layersof the inorganic material. Alternatively, direct bonding means fixingthe two substrates with lenses 41 by forming a silicon-oxygen covalentbond or a silicon-silicon covalent bond between silicon oxide layers orsilicon nitride layers disposed on the surfaces of the two substrateswith lenses 41. Alternatively, or in addition, direct bonding may referto substrates being directly bonded.

In order to realize dehydration condensation based on attachment andheating, in the present embodiment, lenses are formed in a substratestate using a substrate used in the field of manufacturing semiconductordevices and flat-panel display devices, dehydration condensation basedon attachment and heating is realized in a substrate state, and bondingbased on a covalent bond is realized in a substrate state. The structurein which the layers of an inorganic material formed between the surfacesof the two substrates with lenses 41 are bonded by a covalent bond hasan effect or an advantage that the structure suppresses a deformationcaused by curing shrinkage of the resin 513 in the entire substrate anda deformation caused by thermal expansion of the resin 513 during actualuse, which may occur when the technique described in FIG. 2, disclosedin Patent Literature 1 is used.

FIGS. 5 and 6 are diagrams illustrating a step of combining the stackedlens structure 11 and the light receiving elements 12 to form the cameramodule 1A illustrated in FIGS. 1A and 1B.

First, as illustrated in FIG. 5, a plurality of substrates with lenses41W on which a plurality of lenses 21 (not illustrated) is formed in aplane direction are prepared and are stacked together. In this way, astacked lens structure 11W in a substrate state in which a plurality ofsubstrates with lenses 41W in a substrate state is stacked is obtained.

Subsequently, as illustrated in FIG. 6, a sensor substrate 43W in asubstrate state in which a plurality of light receiving elements 12 isformed in a plane direction is manufactured and prepared separately fromthe stacked lens structure 11W in the substrate state illustrated inFIG. 5.

Moreover, the sensor substrate 43W in the substrate state and thestacked lens structure 11W in the substrate state are stacked andattached together, and external terminals are attached to respectivemodules of the attached substrates to obtain a camera module 44W in asubstrate state.

Finally, the camera module 44W in the substrate state is divided intorespective modules or chips. The divided camera module 44 is enclosed ina housing (not illustrated) prepared separately whereby a final cameramodule 44 is obtained.

In the present specification and the drawings, for example, componentsdenoted by reference numerals with “W” added thereto like the substratewith lenses 41W, for example, indicate that the components are in asubstrate state (wafer state), and components denoted by referencenumerals without “W” like the substrate with lenses 41, for example,indicate that the components are divided into respective modules orchips. The same is applied for the sensor substrate 43W, the cameramodule 44W, and the like.

FIG. 7 is a diagram illustrating another step of combining the stackedlens structure 11 and the light receiving elements 12 to form the cameramodule 1A illustrated in FIGS. 1A and 1B.

First, similarly to the above-described step, a stacked lens structure11W in a substrate state on which a plurality of substrates with lenses41W in a substrate state are stacked is manufactured.

Subsequently, the stacked lens structure 11W in the substrate state isdivided into individual pieces.

Moreover, a sensor substrate 43W in a substrate state is manufacturedand prepared separately from the stacked lens structure 11W in thesubstrate state.

Moreover, the divided stacked lens structures 11 are mounted one by oneon the respective light receiving elements 12 of the sensor substrate43W in the substrate state.

Finally, the sensor substrate 43W in the substrate state on which thedivided stacked lens structures 11 are mounted is divided intorespective modules or chips. The divided sensor substrate 43 on whichthe stacked lens structure 11 is mounted is enclosed in a housing (notillustrated) prepared separately and external terminals are attachedthereto to obtain a final camera module 44.

Further, as another example of the step of combining the stacked lensstructure 11 and the light receiving elements 12 to form the cameramodule 1A illustrated in FIGS. 1A and 1B, a sensor substrate 43W in asubstrate state illustrated in FIG. 7 may be divided into individuallight receiving elements 12, and the divided stacked lens structures 11may be mounted on the individual light receiving elements 12 to obtain adivided camera module 44.

FIGS. 8A to 8H are diagrams illustrating a configuration of thesubstrate with lenses 41 of the camera module 1A.

FIG. 8A is the same schematic diagram as FIG. 1A, illustrating aconfiguration of the camera module 1A.

FIG. 8B is the same schematic cross-sectional view as FIG. 1B, of thecamera module 1A.

As illustrated in FIG. 8B, the camera module 1A is a multi-ocular cameramodule including a plurality of optical units 13 having one opticalaxis, formed by combining a plurality of lenses 21. The stacked lensstructure 11 includes twenty five optical units 13 in total, fiveoptical units in vertical and horizontal directions each.

In the camera module 1A, the optical axes of the plurality of opticalunits 13 are disposed so as to spread toward the outer side of themodule. Due to this, it is possible to photograph a wide-angle image.

Although the stacked lens structure 11 illustrated in FIG. 8B has astructure in which only three substrates with lenses 41 are stacked forthe sake of simplicity, a larger number of substrates with lenses 41 maynaturally be stacked.

FIGS. 8C to 8E are diagrams illustrating planar shapes of the threesubstrates with lenses 41 that form the stacked lens structure 11.

FIG. 8C is a plan view of the substrate with lenses 41 on the top layeramong the three layers, FIG. 8D is a plan view of the substrate withlenses 41 on the middle layer, and FIG. 8E is a plan view of thesubstrate with lenses 41 on the bottom layer. Since the camera module 1is a multi-ocular wide-angle camera module, the diameter of the lens 21and the lens-to-lens pitch increase as it ascends from the bottom layerto the top layer.

FIGS. 8F to 8H are plan views of the substrates with lenses 41W in thesubstrate state, for obtaining the substrates with lenses 41 illustratedin FIGS. 8C to 8E, respectively.

The substrate with lenses 41W illustrated in FIG. 8F illustrates thesubstrate state corresponding to the substrate with lenses 41illustrated in FIG. 8C, the substrate with lenses 41W illustrated inFIG. 8G illustrates the substrate state corresponding to the substratewith lenses 41 illustrated in FIG. 8D, and the substrate with lenses 41Willustrated in FIG. 8H illustrates the substrate state corresponding tothe substrate with lenses 41 illustrated in FIG. 8E.

The substrates with lenses 41W in the substrate state, illustrated inFIGS. 8F to 8H are configured to obtain eight camera modules 1Aillustrated in FIG. 8A for one substrate.

It can be understood that between the substrates with lenses 41W of FIG.8F to 8H, the lens-to-lens pitch of the substrate with lenses 41W on thetop layer, in the substrates with lenses 41 of respective modules isdifferent from that of the substrate with lenses 41W on the bottomlayer, and that in each substrate with lenses 41W, the arrangement pitchof the substrates with lenses 41 of the respective modules is constantfrom the substrate with lenses 41W on the top layer to the substratewith lenses 41W on the bottom layer.

2. Second Embodiment of Camera Module

FIGS. 9A to 9H are diagrams illustrating a second embodiment of a cameramodule which uses a stacked lens structure to which the presenttechnique is applied.

FIG. 9A is a schematic diagram illustrating an appearance of a cameramodule 1B as the second embodiment of the camera module 1. FIG. 9B is aschematic cross-sectional view of the camera module 1B.

The camera module 1B includes two optical units 13. The two opticalunits 13 include a diaphragm plate 51 on the top layer of the stackedlens structure 11. An opening 52 is formed in the diaphragm plate 51.

Although the camera module 1B includes two optical units 13, the twooptical units 13 have different optical parameters. That is, the cameramodule 1B includes two optical units 13 having different opticalperformances. The two types of optical units 13 may include an opticalunit 13 having a short focal distance for photographing a close-rangeview and an optical unit 13 having a long focal distance forphotographing a distant view.

In the camera module 1B, since the optical parameters of the two opticalunits 13 are different, the numbers of lenses 21 of the two opticalunits 13 are different as illustrated in FIG. 9B. Moreover, in thelenses 21 on the same layer of the stacked lens structure 11 included inthe two optical units 13, at least one of the diameter, the thickness,the surface shape, the volume, and the distance between adjacent lensesmay be different. Due to this, for example, the lenses 21 of the cameramodule 1B may have such a planar shape that the two optical units 13 mayhave lenses 21 having the same diameter as illustrated in FIG. 9C andmay have lenses 21 having different shapes as illustrated in FIG. 9D,and one of the two optical units 13 may have a void 21X without havingthe lens 21 as illustrated in FIG. 9E.

FIGS. 9F to 9H are plan views of the substrates with lenses 41W in asubstrate state, for obtaining the substrates with lenses 41 illustratedin FIGS. 9C to 9E, respectively.

The substrate with lenses 41W illustrated in FIG. 9F illustrates thesubstrate state corresponding to the substrate with lenses 41illustrated in FIG. 9C, the substrate with lenses 41W illustrated inFIG. 9G illustrates the substrate state corresponding to the substratewith lenses 41 illustrated in FIG. 9D, and the substrate with lenses 41Willustrated in FIG. 9H illustrates the substrate state corresponding tothe substrate with lenses 41 illustrated in FIG. 9E.

The substrates with lenses 41W in the substrate state illustrated inFIGS. 9F to 9H are configured to obtain sixteen camera modules 1Billustrated in FIG. 9A for one substrate.

As illustrated in FIGS. 9F to 9H, in order to form the camera module 1B,lenses having the same shape or lenses having different shapes may beformed on the entire surface of the substrate with lenses 41W in thesubstrate state and lenses may be formed or not.

3. Third Embodiment of Camera Module

FIGS. 10A to 10F are diagrams illustrating a third embodiment of acamera module which uses a stacked lens structure to which the presenttechnique is applied.

FIG. 10A is a schematic diagram illustrating an appearance of a cameramodule 1C as the third embodiment of the camera module 1. FIG. 10B is aschematic cross-sectional view of the camera module 1C.

The camera module 1C includes four optical units 13 in total, two invertical and horizontal directions each, on a light incidence surface.The lenses 21 have the same shape in the four optical units 13.

Although the four optical units 13 include a diaphragm plate 51 on thetop layer of the stacked lens structure 11, the sizes of the openings 52of the diaphragm plates 51 are different among the four optical units13. Due to this, the camera module 1C can realize the following cameramodule 1C, for example. That is, in an anti-crime surveillance camera,for example, in the camera module 1C which uses light receiving elements12 including a light receiving pixel that includes three types of RGBcolor filters and receives three types of RGB light beams for thepurpose of monitoring color images in the day time and a light receivingpixel that does not include RGB color filters for the purpose ofmonitoring monochrome images in the night time, it is possible toincrease the size of the openings of the diaphragms of pixels forphotographing monochrome images in the night time where the illuminanceis low. Due to this, for example, the lenses 21 of one camera module 1Chave such a planar shape that the lenses 21 included in the four opticalunits 13 have the same diameter as illustrated in FIG. 10C, and the sizeof the opening 52 of the diaphragm plate 51 is different depending onthe optical unit 13 as illustrated in FIG. 10D.

FIG. 10E is a plan view of the substrate with lenses 41W in thesubstrate state, for obtaining the substrate with lenses 41 illustratedin FIG. 10C. FIG. 10F is a plan view of the diaphragm plate 51W in thesubstrate state, for obtaining the diaphragm plate 51 illustrated inFIG. 10D.

The substrate with lenses 41W in the substrate state illustrated in FIG.10E and the diaphragm plate 51W in the substrate state illustrated inFIG. 10F are configured to obtain eight camera modules 1C illustrated inFIG. 10A for one substrate.

As illustrated in FIG. 10F, in the diaphragm plate 51W in the substratestate, in order to form the camera module 1C, the sizes of the openings52 can be set to be different for the respective optical units 13included in the camera module 1C.

4. Fourth Embodiment of Camera Module

FIGS. 11A to 11D are diagrams illustrating a fourth embodiment of acamera module which uses a stacked lens structure to which the presenttechnique is applied.

FIG. 11A is a schematic diagram illustrating an appearance of a cameramodule 1D as the fourth embodiment of the camera module 1. FIG. 11B is aschematic cross-sectional view of the camera module 1D.

The camera module 1D includes four optical units 13 in total, two invertical and horizontal directions each, on a light incidence surfacesimilarly to the camera module 1C. The lenses 21 have the same shape andthe openings 52 of the diaphragm plates 51 have the same size in thefour optical units 13.

In the camera module 1D, the optical axes of the two sets of opticalunits 13 disposed in the vertical and horizontal directions of the lightincidence surface extend in the same direction. One-dot chain lineillustrated in FIG. 11B indicates the optical axis of each of theoptical units 13. The camera module 1D having such a structure is idealfor photographing a higher resolution image using a super-resolutiontechnique than photographing using one optical unit 13.

In the camera module 1D, it is possible to obtain a plurality of imageswhich are not necessarily identical while the optical axes beingdirected in the same direction by photographing images using a pluralityof light receiving elements 12 disposed at different positions while theoptical axes in each of the vertical and horizontal directions beingdirected in the same direction or by photographing images using lightreceiving pixels in different regions of one light receiving element 12.By combining image data of respective places, of the plurality ofnon-identical images, it is possible to obtain a high-resolution image.Due to this, the lenses 21 of one camera module 1D preferably have thesame planar shape in the four optical units 13 as illustrated in FIG.11C.

FIG. 11D is a plan view of the substrate with lenses 41W in thesubstrate state, for obtaining the substrate with lenses 41 illustratedin FIG. 11C. The substrate with lenses 41W in the substrate state isconfigured to obtain eight camera modules 1D illustrated in FIG. 11A forone substrate.

As illustrated in FIG. 11D, in the substrate with lenses 41W in thesubstrate state, in order to form the camera module 1D, the cameramodule 1D includes a plurality of lenses 21 and a plurality of modulelens groups is disposed on the substrate at a fixed pitch.

5. Fifth Embodiment of Camera Module

FIGS. 12A to 12D are diagrams illustrating a fifth embodiment of acamera module which uses a stacked lens structure to which the presenttechnique is applied.

FIG. 12A is a schematic diagram illustrating an appearance of a cameramodule 1E as a fifth embodiment of the camera module 1. FIG. 12B is aschematic cross-sectional view of the camera module 1E.

The camera module 1E is a monocular camera module in which one opticalunit 13 having one optical axis is provided in the camera module 1E.

FIG. 12C is a plan view of the substrate with lenses 41, illustrating aplanar shape of the lenses 21 of the camera module 1E. The camera module1E includes one optical unit 13.

FIG. 12D is a plan view of the substrate with lenses 41W in thesubstrate state, for obtaining the substrate with lenses 41 illustratedin FIG. 12C. The substrate with lenses 41W in the substrate state isconfigured to obtain thirty two camera modules 1E illustrated in FIG.12A for one substrate.

As illustrated in FIG. 12D, in the substrate with lenses 41W in thesubstrate state, a plurality of lenses 21 for the camera module 1E isdisposed on the substrate at a fixed pitch.

6. Detailed Configuration of Camera Module of Fourth Embodiment

Next, a detailed configuration of the camera module 1D according to thefourth embodiment illustrated in FIGS. 11A to 11D will be described withreference to FIG. 13.

FIG. 13 is a cross-sectional view of the camera module 1D illustrated inFIG. 11B.

The camera module 1D is configured to include a stacked lens structure11 in which a plurality of substrates with lenses 41 a to 41 e arestacked and a light receiving element 12. The stacked lens structure 11includes a plurality of optical units 13. One-dot chain line 84indicates an optical axis of each of the optical units 13. The lightreceiving element 12 is disposed on the lower side of the stacked lensstructure 11. In the camera module 1D, light entering the camera module1D from above passes through the stacked lens structure 11 and the lightis received by the light receiving element 12 disposed on the lower sideof the stacked lens structure 11.

The stacked lens structure 11 includes five stacked substrates withlenses 41 a to 41 e. When the five substrates with lenses 41 a to 41 eare not distinguished particularly, the substrates with lenses will bereferred to simply as substrates with lenses 41.

A cross-sectional shape of a through-hole 83 of the substrates withlenses 41 that form the stacked lens structure 11 has a so-calleddownward tapered shape such that an opening width decreases as itadvances toward the lower side (the side on which the light receivingelement 12 is disposed).

A diaphragm plate 51 is disposed on the stacked lens structure 11. Thediaphragm plate 51 has a layer formed of a material having a lightabsorbing property or a light blocking property, for example. An opening52 is formed in the diaphragm plate 51.

The light receiving element 12 is formed of a front or back-illuminatedcomplementary metal oxide semiconductor (CMOS) image sensor, forexample. On-chip lenses 71 are formed on a surface on an upper side ofthe light receiving element 12 close to the stacked lens structure 11,and external terminals 72 for inputting and outputting signals areformed on a surface on a lower side of the light receiving element 12.

The stacked lens structure 11, the light receiving element 12, thediaphragm plate 51, and the like are accommodated in a lens barrel 74.

A structure material 73 is disposed on the upper side of the lightreceiving element 12. The stacked lens structure 11 and the lightreceiving element 12 are fixed by the structure material 73. Thestructure material 73 is an epoxy-based resin, for example.

In the present embodiment, although the stacked lens structure 11includes five stacked substrates with lenses 41 a to 41 e, the number ofstacked substrates with lenses 41 is not particularly limited as long astwo substrates with lenses or more are stacked.

Each of the substrates with lenses 41 that form the stacked lensstructure 11 is configured by adding a lens resin portion 82 to asupport substrate 81. The support substrate 81 has the through-hole 83,and the lens resin portion 82 is formed on the inner side of thethrough-hole 83. The lens resin portion 82 is a portion which includesthe above-described lenses 21 and extends up to the support substrate 81and which is integrated with a portion that supports the lens 21 by amaterial that forms the lens 21.

When the support substrates 81, the lens resin portions 82, or thethrough-holes 83 of the respective substrates with lenses 41 a to 41 eare distinguished, the respective components will be referred to assupport substrates 81 a to 81 e, lens resin portions 82 a to 82 e, orthrough-holes 83 a to 83 e so as to correspond to the substrates withlenses 41 a to 41 e as illustrated in FIG. 13.

Detailed Description of Lens Resin Portion

Next, the shape of the lens resin portion 82 will be described by way ofan example of the lens resin portion 82 a of the substrate with lenses41 a.

FIG. 14 illustrates a plan view and cross-sectional views of the supportsubstrate 81 a and the lens resin portion 82 a that form the substratewith lenses 41 a.

The cross-sectional views of the support substrate 81 a and the lensresin portion 82 a illustrated in FIG. 14 are cross-sectional viewstaken along lines B-B′ and C-C′ in the plan view.

The lens resin portion 82 a is a portion formed integrally by thematerial that forms the lens 21 and includes a lens portion 91 and asupport portion 92. In the above description, the lens 21 corresponds tothe entire lens portion 91 or the entire lens resin portion 82 a.

The lens portion 91 is a portion having the performance of a lens, andin other words, is “a portion that refracts light so that lightconverges or diverges” or “a portion having a curved surface such as aconvex surface, a concave surface, or an aspherical surface, or aportion in which a plurality of polygons used in a lens which uses aFresnel screen or a diffraction grating are continuously disposed”.

The support portion 92 is a portion that extends from the lens portion91 up to the support substrate 81 a to support the lens portion 91. Thesupport portion 92 includes an arm portion 101 and a leg portion 102 andis positioned at the outer circumference of the lens portion 91.

The arm portion 101 is a portion that is disposed on the outer side ofthe lens portion 91 in contact with the lens portion 91 and extendsoutward from the lens portion 91 in a constant thickness. The legportion 102 is a portion of the support portion 92 other than the armportion 101 and includes a portion that is in contact with the side wallof the through-hole 83 a. The thickness of the resin in the leg portion102 is preferably larger than that of the arm portion 101.

The planar shape of the through-hole 83 a formed in the supportsubstrate 81 a is circular, and the cross-sectional shape is naturallythe same regardless of the diametrical direction. The cross-sectionalshape of the lens resin portion 82 a which is the shape determined bythe upper and lower molds during forming of a lens is the sameregardless of the diametrical direction.

FIG. 15 is a cross-sectional view illustrating the stacked lensstructure 11 and the diaphragm plate 51 which are part of the cameramodule 1D illustrated in FIG. 13.

In the camera module 1D, after light entering the module is narrowed bythe diaphragm plate 51, the light is widened inside the stacked lensstructure 11 and is incident on the light receiving element 12 (notillustrated in FIG. 15) disposed on the lower side of the stacked lensstructure 11. That is, in a general view of the entire stacked lensstructure 11, the light entering the module moves while wideningsubstantially in a fan shape toward the lower side from the opening 52of the diaphragm plate 51. Due to this, as an example of the size of thelens resin portion 82 provided in the stacked lens structure 11, in thestacked lens structure 11 illustrated in FIG. 15, the lens resin portion82 a provided in the substrate with lenses 41 a disposed immediatelybelow the diaphragm plate 51 is the smallest, and the lens resin portion82 e provided in the substrate with lenses 41 e disposed on the bottomlayer of the stacked lens structure 11 is the largest.

If the lens resin portion 82 of the substrate with lenses 41 has aconstant thickness, it is more difficult to manufacture a larger lensthan a smaller lens. This is because a large lens is likely to bedeformed due to a load applied to the lens when manufacturing the lensand it is difficult to maintain the strength. Due to this, it ispreferable to increase the thickness of a large lens to be larger thanthe thickness of a small lens.

Thus, in the stacked lens structure 11 illustrated in FIG. 15, thethickness of the lens resin portion 82 e provided in the substrate withlenses 41 e disposed on the bottom layer is the largest among the lensresin portions 82.

The stacked lens structure 11 illustrated in FIG. 15 has at least one ofthe following features in order to increase the degree of freedom in alens design.

(1) The thickness of the support substrate 81 is different at leastamong the plurality of substrates with lenses 41 that forms the stackedlens structure 11. For example, the thickness of the support substrate81 in the substrate with lenses 41 on the bottom layer is the largest.(2) An opening width of the through-hole 83 provided in the substratewith lenses 41 is different at least among the plurality of substrateswith lenses 41 that forms the stacked lens structure 11. For example,the opening width of the through-hole 83 in the substrate with lenses 41on the bottom layer is the largest.(3) The diameter of the lens portion 91 provided in the substrate withlenses 41 is different at least among the plurality of substrates withlenses 41 that forms the stacked lens structure 11. For example, thediameter of the lens portion 91 in the substrate with lenses 41 on thebottom layer is the largest.(4) The thickness of the lens portion 91 provided in the substrate withlenses 41 is different at least among the plurality of substrates withlenses 41 that forms the stacked lens structure 11. For example, thethickness of the lens portion 91 in the substrate with lenses 41 on thebottom layer is the largest.(5) The distance between the lenses provided in the substrate withlenses 41 is different at least among the plurality of substrates withlenses 41 that forms the stacked lens structure 11.(6) The volume of the lens resin portion 82 provided in the substratewith lenses 41 is different at least among the plurality of substrateswith lenses 41 that forms the stacked lens structure 11. For example,the volume of the lens resin portion 82 in the substrate with lenses 41on the bottom layer is the largest.(7) The material of the lens resin portion 82 provided in the substratewith lenses 41 is different at least among the plurality of substrateswith lenses 41 that forms the stacked lens structure 11.

In general, light incident on a camera module includes vertical incidentlight and oblique incident light. A large part of the oblique incidentlight strikes the diaphragm plate 51 and is absorbed therein or isreflected outside the camera module 1D. The oblique incident light whichis not narrowed by the diaphragm plate 51 may strike the side wall ofthe through-hole 83 depending on an incidence angle thereof and may bereflected therefrom.

The moving direction of the reflected light of the oblique incidentlight is determined by the incidence angle of oblique incident light 85and the angle of the side wall of the through-hole 83 as illustrated inFIG. 13. When the opening of the through-hole 83 has a so-called fanshape such that the opening width increases as it advances from theincidence side toward the light receiving element 12, if the obliqueincident light 85 of a specific incidence angle which is not narrowed bythe diaphragm plate 51 strikes the side wall of the through-hole 83, theoblique incident light may be reflected in the direction of the lightreceiving element 12, and the reflected light may become stray light ornoise light.

However, in the stacked lens structure 11 illustrated in FIG. 13, asillustrated in FIG. 15, the through-hole 83 has a so-called downwardtapered shape such that the opening width decreases as it advancestoward the lower side (the side on which the light receiving element 12is disposed). In the case of this shape, the oblique incident light 85striking the side wall of the through-hole 83 is reflected in the upperdirection (so-called the incidence side direction) rather than the lowerdirection (so-called the direction of the light receiving element 12).Due to this, an effect or an advantage of suppressing the occurrence ofstray light or noise light is obtained.

A light absorbing material may be disposed in the side wall of thethrough-hole 83 of the substrate with lenses 41 in order to suppresslight which strikes the side wall and is reflected therefrom.

As an example, when light (for example, visible light) of a wavelengththat is to be received when the camera module 1D is used as a camera isfirst light and light (for example, UV light) of a wavelength differentfrom the first light is second light, a material obtained by dispersingcarbon particles as a material absorbing the first light (visible light)into a resin that is cured by the second light (UV light) may be appliedor sprayed to the surface of the support substrate 81, the resin of theside wall portion only of the through-hole 83 may be cured byirradiation with the second light (UV light), and the resin in the otherregion may be removed. In this way, a layer of a material having aproperty of absorbing the first light (visible light) may be formed onthe side wall of the through-hole 83.

The stacked lens structure 11 illustrated in FIG. 15 is an example of astructure in which the diaphragm plate 51 is disposed on top of theplurality of stacked substrates with lenses 41. The diaphragm plate 51may be disposed by being inserted in any of the intermediate substrateswith lenses 41 rather than on top of the plurality of stacked substrateswith lenses 41.

As still another example, instead of providing the planar diaphragmplate 51 separately from the substrate with lenses 41, a layer of amaterial having a light absorbing property may be formed on the surfaceof the substrate with lenses 41 so as to function as a diaphragm. Forexample, a material obtained by dispersing carbon particles as amaterial absorbing the first light (visible light) in a resin that iscured by the second light (UV light) may be applied or sprayed to thesurface of the substrate with lenses 41, the resin in a region otherthan a region through which light is to pass when the layer functions asa diaphragm may be irradiated with the second light (UV light) to curethe resin so as to remain, and the resin in the region that is not cured(that is, the region through which light is to pass when the layerfunctions as a diaphragm) may be removed. In this way, the diaphragm maybe formed on the surface of the substrate with lenses 41.

The substrate with lenses 41 in which the diaphragm is formed on thesurface may be the substrate with lenses 41 disposed on the top layer ofthe stacked lens structure 11 or may be the substrate with lenses 41which is an inner layer of the stacked lens structure 11.

The stacked lens structure 11 illustrated in FIG. 15 has a structure inwhich the substrates with lenses 41 are stacked.

As another embodiment, the stacked lens structure 11 may have astructure which includes a plurality of substrates with lenses 41 and atleast one support substrate 81 which does not have the lens resinportion 82. In this structure, the support substrate 81 which does nothave the lens resin portion 82 may be disposed on the top layer or thebottom layer of the stacked lens structure 11 and may be disposed as aninner layer of the stacked lens structure 11. This structure provides aneffect or an advantage, for example, that the distance between theplurality of lenses included in the stacked lens structure 11 and thedistance between the lens resin portion 82 on the bottom layer of thestacked lens structure 11 and the light receiving element 12 disposed onthe lower side of the stacked lens structure 11 can be set arbitrarily.

Alternatively, this structure provides an effect or an advantage that,when the opening width of the support substrate 81 which does not havethe lens resin portion 82 is set appropriately and a material having alight absorbing property is disposed in a region excluding the opening,the material can function as a diaphragm plate.

7. Sixth Embodiment of Camera Module

FIG. 16 is a diagram illustrating a sixth embodiment of a camera modulewhich uses a stacked lens structure to which the present technique isapplied.

In FIG. 16, the portions corresponding to those of the fourth embodimentillustrated in FIG. 13 will be denoted by the same reference numerals,and different portions from those of the camera module 1D illustrated inFIG. 13 will be described mainly.

In a camera module 1F illustrated in FIG. 16, similarly to the cameramodule 1D illustrated in FIG. 13, after incident light is narrowed bythe diaphragm plate 51, the light is widened inside the stacked lensstructure 11 and is incident on the light receiving element 12 disposedon the lower side of the stacked lens structure 11. That is, in ageneral view of the entire stacked lens structure 11, the light moveswhile widening substantially in a fan shape toward the lower side fromthe opening 52 of the diaphragm plate 51.

The camera module 1F illustrated in FIG. 16 is different from the cameramodule 1D illustrated in FIG. 13 in that the cross-sectional shape ofthe through-holes 83 of the substrates with lenses 41 that form thestacked lens structure 11 has a so-called fan shape such that theopening width increases as it advances toward the lower side (the sideon which the light receiving element 12 is disposed).

The stacked lens structure 11 of the camera module 1F has a structure inwhich incident light moves while widening in a fan shape from theopening 52 of the diaphragm plate 51 toward the lower side. Thus, such afan shape that the opening width of the through-hole 83 increases towardthe lower side makes the support substrate 81 less likely to obstruct anoptical path than such a downward tapered shape that the opening widthof the through-hole 83 decreases toward the lower side. Due to this, aneffect of increasing the degree of freedom in a lens design is obtained.

Moreover, in the case of the downward tapered shape that the openingwidth of the through-hole 83 decreases toward the lower side, thecross-sectional area in the substrate plane direction of the lens resinportion 82 including the support portion 92 has a specific size in thelower surface of the lens resin portion 82 in order to transmit lightentering the lens 21. On the other hand, the cross-sectional areaincreases as it advances from the lower surface of the lens resinportion 82 toward the upper surface.

In contrast, in the case of the fan shape that the opening width of thethrough-hole 83 increases toward the lower side, the cross-sectionalarea in the lower surface of the lens resin portion 82 is substantiallythe same as the case of the downward tapered shape. However, thecross-sectional area decreases as it advances from the lower surface ofthe lens resin portion 82 toward the upper surface.

Due to this, the structure in which the opening width of thethrough-hole 83 increases toward the lower side provides an effect or anadvantage that the size of the lens resin portion 82 including thesupport portion 92 can be reduced. As a result, it is possible toprovide an effect or an advantage that the above-described difficulty informing lenses, occurring when the lens is large can be reduced.

8. Seventh Embodiment of Camera Module

FIG. 17 is a diagram illustrating a seventh embodiment of a cameramodule which uses a stacked lens structure to which the presenttechnique is applied.

In FIG. 17, the portions corresponding to those of the fourth embodimentillustrated in FIG. 13 will be denoted by the same reference numerals,and different portions from those of the camera module 1D illustrated inFIG. 13 will be described mainly.

In a camera module 1G illustrated in FIG. 17, the shapes of the lensresin portions 82 and the through-holes 83 of the substrates with lenses41 that form the stacked lens structure 11 are different from those ofthe camera module 1D illustrated in FIG. 13.

The stacked lens structure 11 of the camera module 1G includes both asubstrate with lenses 41 in which the through-hole 83 has a so-calleddownward tapered shape such that the opening width decreases toward thelower side (the side on which the light receiving element 12 isdisposed) and a substrate with lenses 41 in which the through-hole 83has a so-called fan shape such that the opening width increases towardthe lower side.

In the substrate with lenses 41 in which the through-hole 83 has aso-called downward tapered shape that the opening width decreases towardthe lower side, the oblique incident light 85 striking the side wall ofthe through-hole 83 is reflected in the upper direction (so-called theincidence side direction) as described above. Due to this, an effect oran advantage of suppressing the occurrence of stray light or noise lightis obtained.

In the stacked lens structure 11 illustrated in FIG. 17, a plurality ofsubstrates with lenses 41 in which the through-hole 83 has the so-calleddownward tapered shape that the opening width decreases toward the lowerside is used particularly on the upper side (the incidence side) amongthe plurality of substrates with lenses 41 that forms the stacked lensstructure 11.

In the substrate with lenses 41 in which the through-hole 83 has theso-called fan shape that the opening width increases toward the lowerside, the support substrate 81 provided in the substrate with lenses 41is rarely likely to obstruct the optical path as described above. Due tothis, an effect or an advantage of increasing the degree of freedom in alens design or reducing the size of the lens resin portion 82 includingthe support portion 92 provided in the substrate with lenses 41 isobtained.

In the stacked lens structure 11 illustrated in FIG. 17, light moveswhile being widened in a fan shape from the diaphragm toward the lowerside. Thus, the lens resin portion 82 provided in several substrateswith lenses 41 disposed on the lower side among the plurality ofsubstrates with lenses 41 that forms the stacked lens structure 11 has alarge size. When the through-hole 83 having the fan shape is used insuch a large lens resin portion 82, a remarkable effect of reducing thesize of the lens resin portion 82 is obtained.

Thus, in the stacked lens structure 11 illustrated in FIG. 17, aplurality of substrates with lenses 41 in which the through-hole 83 hasthe so-called fan shape that the opening width increases toward thelower side is used particularly on the lower side among the plurality ofsubstrates with lenses 41 that forms the stacked lens structure 11.

9. Detailed Configuration of Substrate with Lenses

Next, a detailed configuration of the substrate with lenses 41 will bedescribed.

FIGS. 18A to 18C are cross-sectional views illustrating a detailedconfiguration of the substrate with lenses 41.

Although FIGS. 18A to 18C illustrate the substrate with lenses 41 a onthe top layer among the five substrates with lenses 41 a to 41 e, theother substrates with lenses 41 are configured similarly.

The substrate with lenses 41 may have any one of the configurationsillustrated in FIGS. 18A to 18C.

In the substrate with lenses 41 illustrated in FIG. 18A, the lens resinportion 82 is formed so as to block the through-hole 83 when seen fromthe upper surface in relation to the through-hole 83 formed in thesupport substrate 81. As described with reference to FIG. 14, the lensresin portion 82 includes the lens portion 91 (not illustrated) at thecenter and the support portion 92 (not illustrated) in the periphery.

A film 121 having a light absorbing property or a light blockingproperty is formed on the side wall of the through-hole 83 of thesubstrate with lenses 41 in order to prevent ghost or flare resultingfrom reflection of light. Such a film 121 will be referred to as a lightblocking film 121 for the sake of convenience.

An upper surface layer 122 containing oxides, nitrides, or otherinsulating materials is formed on an upper surface of the supportsubstrate 81 and the lens resin portion 82, and a lower surface layer123 containing oxides, nitrides, or other insulating materials is formedon a lower surface of the support substrate 81 and the lens resinportion 82.

As an example, the upper surface layer 122 forms an anti-reflection filmin which a low refractive index film and a high refractive index filmare stacked alternately in a plurality of layers. The anti-reflectionfilm can be formed by alternately stacking a low refractive index filmand a high refractive index film in four layers in total. For example,the low refractive index film is formed of an oxide film such as SiO_(x)(1≤x≤2), SiOC, or SiOF, and the high refractive index film is formed ofa metal oxide film such as TiO, TaO, or Nb₂O₅.

The configuration of the upper surface layer 122 may be designed so asto obtain a desired anti-reflection performance using an opticalsimulation, for example, and the material, the thickness, the number ofstacked layers, and the like of the low refractive index film and thehigh refractive index film are not particularly limited. In the presentembodiment, the top surface of the upper surface layer 122 is a lowrefractive index film which has a thickness of 20 to 1000 nm, forexample, a density of 2.2 to 2.5 g/cm³, for example, and a flatness ofapproximately 1 nm or smaller in root mean roughness Rq (RMS), forexample. Moreover, the upper surface layer 122 also serve as a bondingfilm when it is bonded to other substrates with lenses 41, which will bedescribed in detail later.

As an example, the upper surface layer 122 may be an anti-reflectionfilm in which a low refractive index film and a high refractive indexfilm are stacked alternately in a plurality of layers, and among suchanti-reflection films, the upper surface layer 122 may be ananti-reflection film of an inorganic material. As another example, theupper surface layer 122 may be a single-layer film containing oxides,nitrides, or other insulating materials, and among such single-layerfilms, the upper surface layer 122 may be a film of an inorganicmaterial.

As an example, the lower surface layer 123 may be an anti-reflectionfilm in which a low refractive index film and a high refractive indexfilm are stacked alternately in a plurality of layers, and among suchanti-reflection films, the lower surface layer 123 may be ananti-reflection film of an inorganic material. As another example, thelower surface layer 123 may be a single-layer film containing oxides,nitrides, or other insulating materials, and among such single-layerfilms, the lower surface layer 123 may be a film of an inorganicmaterial.

As for the substrates with lenses 41 illustrated in FIGS. 18B and 18C,only different portions from those of the substrate with lenses 41illustrated in FIG. 18A will be described.

In the substrate with lenses 41 illustrated in FIG. 18B, a film formedon the lower surface of the support substrate 81 and the lens resinportion 82 is different from that of the substrate with lenses 41illustrated in FIG. 18A.

In the substrate with lenses 41 illustrated in FIG. 18B, a lower surfacelayer 124 containing oxides, nitrides, or other insulating materials isformed on the lower surface of the support substrate 81, and the lowersurface layer 124 is not formed on the lower surface of the lens resinportion 82. The lower surface layer 124 may be formed of the samematerial as or a different material from the upper surface layer 122.

Such a structure can be formed by a manufacturing method of forming thelower surface layer 124 on the lower surface of the support substrate 81before forming the lens resin portion 82 and then forming the lens resinportion 82. Alternatively, such a structure can be formed by forming amask on the lens resin portion 82 after forming the lens resin portion82 and then depositing a film that forms the lower surface layer 124 tothe lower surface of the support substrate 81 according to PVD, forexample, in a state in which a mask is not formed on the supportsubstrate 81.

In the substrate with lenses 41 illustrated in FIG. 18C, the uppersurface layer 125 containing oxides, nitrides, or other insulatingmaterials is formed on the upper surface of the support substrate 81,and the upper surface layer 125 is not formed on the upper surface ofthe lens resin portion 82.

Similarly, in the lower surface of the substrate with lenses 41, thelower surface layer 124 containing oxides, nitrides, or other insulatingmaterials is formed on the lower surface of the support substrate 81,and the lower surface layer 124 is not formed on the lower surface ofthe lens resin portion 82.

Such a structure can be formed by a manufacturing method of forming theupper surface layer 125 and the lower surface layer 124 on the supportsubstrate 81 before the lens resin portion 82 is formed and then formingthe lens resin portion 82. Alternatively, such a structure can be formedby forming a mask on the lens resin portion 82 after forming the lensresin portion 82 and then depositing a film that forms the upper surfacelayer 125 and the lower surface layer 124 to the surface of the supportsubstrate 81 according to PVD, for example, in a state in which a maskis not formed on the support substrate 81. The lower surface layer 124and the upper surface layer 125 may be formed of the same material ordifferent materials.

The substrate with lenses 41 can be formed in the above-describedmanner.

10. Method of Manufacturing Substrate with Lenses

Next, a method of manufacturing the substrate with lenses 41 will bedescribed with reference to FIGS. 19A and 19B to FIG. 29.

First, a support substrate 81W in a substrate state in which a pluralityof through-holes 83 is formed is prepared. A silicon substrate used ingeneral semiconductor devices, for example, can be used as the supportsubstrate 81W. The support substrate 81W has such as circular shape asillustrated in FIG. 19A, for example, and the diameter thereof is 200 mmor 300 mm, for example. The support substrate 81W may be a glasssubstrate, a resin substrate, or a metal substrate, for example, otherthan the silicon substrate.

Moreover, in the present embodiment, although the planar shape of thethrough-hole 83 is circular as illustrated in FIG. 19A, the planar shapeof the through-hole 83 may be polygonal such as rectangular asillustrated in FIG. 19B.

The opening width of the through-hole 83 may be between approximately100 μm and approximately 20 mm, for example. In this case, for example,approximately 100 to 5,000,000 through-holes 83 can be disposed in thesupport substrate 81W.

In the present specification, the size of the through-hole 83 in theplane direction of the substrate with lenses 41 is referred to as anopening width. The opening width means the length of one side when theplanar shape of the through-hole 83 is rectangular and means thediameter when the planar shape of the through-hole 83 is circular unlessparticularly stated otherwise.

As illustrated in FIGS. 20A to 20C, the through-hole 83 is configuredsuch that a second opening width 132 in a second surface facing a firstsurface of the support substrate 81W is smaller than a first openingwidth 131 in the first surface.

As an example of a three-dimensional shape of the through-hole 83 ofwhich the second opening width 132 is smaller than the first openingwidth 131, the through-hole 83 may have a truncated conical shape asillustrated in FIG. 20A and may have a truncated polygonal pyramidalshape. The cross-sectional shape of the side wall of the through-hole 83may be linear as illustrated in FIG. 20A and may be curved asillustrated in FIG. 20B. Alternatively, the cross-sectional shape mayhave a step as illustrated in FIG. 20C.

When a resin is supplied into the through-hole 83 having such a shapethat the second opening width 132 is smaller than the first openingwidth 131, and the resin is pressed by mold members in oppositedirections from the first and second surfaces to form the lens resinportion 82, the resin that forms the lens resin portion 82 receivesforce from the two facing mold members and is pressed against the sidewall of the through-hole 83. Due to this, it is possible to obtain aneffect of increasing the adhesion strength between the support substrateand the resin that forms the lens resin portion 82.

As another embodiment of the through-hole 83, the through-hole 83 mayhave such a shape that the first opening width 131 is the same as thesecond opening width 132 (that is, a shape that the cross-sectionalshape of the side wall of the through-hole 83 is vertical).

<Through-Hole Forming Method Using Wet-Etching>

The through-holes 83 of the support substrate 81W can be formed byetching the support substrate 81W according to wet-etching.Specifically, before the support substrate 81W is etched, an etchingmask for preventing a non-opening region of the support substrate 81Wfrom being etched is formed on the surface of the support substrate 81W.An insulating film such as a silicon oxide film or a silicon nitridefilm, for example, is used as the material of the etching mask. Theetching mask is formed by forming the layer of an etching mask materialon the surface of the support substrate 81W and opening a pattern thatforms the planar shape of the through-hole 83 in the layer. After theetching mask is formed, the support substrate 81W is etched whereby thethrough-holes 83 are formed in the support substrate 81W.

When single-crystal silicon of which the substrate plane orientation is(100) is used as the support substrate 81W, for example, crystalanisotropic wet-etching which uses an alkaline solution such as KOH maybe used to form the through-hole 83.

When crystal anisotropic wet-etching which uses an alkaline solutionsuch as KOH is performed on the support substrate 81W which issingle-crystal silicon of which the substrate plane orientation is(100), etching progresses so that the (111) plane appears on the openingside wall. As a result, even when the planar shape of the opening of theetching mask is circular or rectangular, the through-holes 83 in whichthe planar shape is rectangular, the second opening width 132 of thethrough-hole 83 is smaller than the first opening width 131, and thethree-dimensional shape of the through-hole 83 has a truncated pyramidalshape or a similar shape are obtained. The angle of the side wall of thethrough-hole 83 having the truncated pyramidal shape is approximately55° with respect to the substrate plane.

As another example of etching for forming the through-hole, wet-etchingwhich uses a chemical liquid capable of etching silicon in an arbitraryshape without any limitation of crystal orientations, disclosed inInternational Patent Publication No. 2011/010739 or the like may beused. Examples of this chemical liquid include a chemical liquidobtained by adding at least one of polyoxyethylene alkylphenyl ethers,polyoxyalkylene alkyl ethers, and polyethylene glycols which aresurfactants to an aqueous solution of TMAH (tetramethylammoniumhydroxide) or a chemical liquid obtained by adding isopropyl alcohols toan aqueous solution of KOH.

When etching for forming the through-holes 83 is performed on thesupport substrate 81W which is single-crystal silicon of which thesubstrate plane orientation is (100) using any one the above-describedchemical liquids, the through-holes 83 in which the planar shape iscircular when the planar shape of the opening of the etching mask iscircular, the second opening width 132 is smaller than the first openingwidth 131, and the three-dimensional shape is a truncated conical shapeor a similar shape are obtained.

When the planar shape of the opening of the etching mask is rectangular,the through-holes 83 in which the planar shape is rectangular, thesecond opening width 132 is smaller than the first opening width 131,and the three-dimensional shape is a truncated pyramidal shape or asimilar shape are obtained. The angle of the side wall of thethrough-hole 83 having the truncated conical shape or the truncatedpyramidal shape is approximately 45° with respect to the substrateplane.

<Through-Hole Forming Method Using Dry-Etching>

In etching for forming the through-holes 83, dry-etching can be alsoused rather than the wet-etching.

A method of forming the through-holes 83 using dry-etching will bedescribed with reference to FIGS. 21A to 21F.

As illustrated in FIG. 21A, an etching mask 141 is formed on one surfaceof the support substrate 81W. The etching mask 141 has a mask pattern inwhich portions that form the through-holes 83 are open.

Subsequently, after a protective film 142 for protecting the side wallof the etching mask 141 is formed as illustrated in FIG. 21B, thesupport substrate 81W is etched to a predetermined depth according todry-etching as illustrated in FIG. 21C. With the dry-etching step,although the protective film 142 on the surface of the support substrate81W and the surface of the etching mask 141 is removed, the protectivefilm 142 on the side surface of the etching mask 141 remains and theside wall of the etching mask 141 is protected. After etching isperformed, as illustrated in FIG. 21D, the protective film 142 on theside wall is removed and the etching mask 141 is removed in a directionof increasing the size of the opening pattern.

Moreover, a protective film forming step, a dry-etching step, and anetching mask removal step illustrated in FIGS. 21B to 21D are repeatedlyperformed a plurality of number of times. In this way, as illustrated inFIG. 21E, the support substrate 81W is etched in a stair shape(concave-convex shape) having periodic steps.

Finally, when the etching mask 141 is removed, the through-holes 83having a stair-shaped side wall are formed in the support substrate 81Was illustrated in FIG. 21F. The width (the width of one step) in theplane direction of the stair shape of the through-hole 83 is betweenapproximately 400 nm and 1 μm, for example.

When the through-holes 83 are formed using the above-describeddry-etching, a protective film forming step, a dry-etching step, and anetching mask removal step are executed repeatedly.

Since the side wall of the through-hole 83 has a periodic stair shape(concave-convex shape), it is possible to suppress reflection ofincident light. If the side wall of the through-hole 83 has aconcave-convex shape of a random size, a void (cavity) is formed in anadhesion layer between the side wall and the lens formed in thethrough-hole 83, and the adhesion to the lens may decrease due to thevoid. However, according to the above-described forming method, sincethe side wall of the through-hole 83 has a periodic concave-convexshape, the adhesion property is improved, and a change in opticalcharacteristics due to a positional shift of lenses can be suppressed.

As examples of the materials used in the respective steps, for example,the support substrate 81W may be single-crystal silicon, the etchingmask 141 may be a photoresist, and the protective film 142 may befluorocarbon polymer formed using gas plasma such as C₄F₈ or CHF₃. Theetching process may use plasma etching which uses gas that contains Fsuch as SF₆/O₂ or C₄F₈/SF₆. The mask removing step may use plasmaetching which uses O₂ gas or gas that contains O₂ such as CF₄/O₂.

Alternatively, the support substrate 81W may be single-crystal silicon,the etching mask 141 may be SiO₂, etching may use plasma that containsCl₂, the protective film 142 may use an oxide film obtained by oxidatingan etching target material using O₂ plasma, the etching process may useplasma using gas that contains Cl₂, and the etching mask removal stepmay use plasma etching which uses gas that contains F such as CF₄/O₂.

As described above, although a plurality of through-holes 83 can besimultaneously formed in the support substrate 81W by wet-etching ordry-etching, through-grooves 151 may be formed in a region in which thethrough-holes 83 are not formed, of the support substrate 81W asillustrated in FIG. 22A.

FIG. 22A is a plan view of the support substrate 81W in which thethrough-groove 151 as well as the through-hole 83 are formed.

For example, as illustrated in FIG. 22A, the through-groove 151 isdisposed only in a portion between the through-holes 83 in each of therow and column directions outside the plurality of through-holes 83disposed in a matrix form.

Moreover, the through-grooves 151 of the support substrate 81W can beformed at the same position in the respective substrates with lenses 41that form the stacked lens structure 11. In this case, in a state inwhich a plurality of support substrates 81W is stacked as the stackedlens structure 11, the through-grooves 151 of the plurality of supportsubstrates 81W pass between the plurality of support substrates 81W asin the cross-sectional view of FIG. 22B.

The through-groove 151 of the support substrate 81W as a portion of thesubstrate with lenses 41 can provide an effect or an advantage ofalleviating a deformation of the substrate with lenses 41 resulting fromstress when the stress that deforms the substrate with lenses 41 isapplied from the outside of the substrate with lenses 41.

Alternatively, the through-groove 151 can provide an effect or anadvantage of alleviating a deformation of the substrate with lenses 41resulting from stress when the stress that deforms the substrate withlenses 41 is generated from the inside of the substrate with lenses 41.

<Method of Manufacturing Substrate with Lenses>

Next, a method of manufacturing the substrate with lenses 41W in asubstrate state will be described with reference to FIGS. 23A to 23G.

First, a support substrate 81W in which a plurality of through-holes 83is formed is prepared as illustrated in FIG. 23A. A light blocking film121 is formed on the side wall of the through-hole 83. Although only twothrough-holes 83 are illustrated in FIGS. 23A to 23G due to limitationof the drawing surface, a number of through-holes 83 are actually formedin the plane direction of the support substrate 81W as illustrated inFIGS. 19A and 19B. Moreover, an alignment mark (not illustrated) forpositioning is formed in a region close to the outer circumference ofthe support substrate 81W.

A front planar portion 171 on an upper side of the support substrate 81Wand a rear planar portion 172 on a lower side thereof are planarsurfaces formed so flat as to allow plasma bonding performed in a laterstep. The thickness of the support substrate 81W also plays the role ofa spacer that determines a lens-to-lens distance when the supportsubstrate 81W is finally divided as the substrate with lenses 41 and issuperimposed on another substrate with lenses 41.

A base material having a low thermal expansion coefficient of 10 ppm/°C. or less is preferably used as the support substrate 81W.

Subsequently, as illustrated in FIG. 23B, the support substrate 81W isdisposed on a lower mold 181 in which a plurality of concave opticaltransfer surfaces 182 is disposed at a fixed interval. Morespecifically, the rear planar portion 172 of the support substrate 81Wand the planar surface 183 of the lower mold 181 are superimposedtogether so that the concave optical transfer surface 182 is positionedinside the through-hole 83 of the support substrate 81W. The opticaltransfer surfaces 182 of the lower mold 181 are formed so as tocorrespond to the through-holes 83 of the support substrate 81W inone-to-one correspondence, and the positions in the plane direction ofthe support substrate 81W and the lower mold 181 are adjusted so thatthe centers of the corresponding optical transfer surface 182 and thethrough-hole 83 are identical in the optical axis direction. The lowermold 181 is formed of a hard mold member and is configured using metal,silicon, quartz, or glass, for example.

Subsequently, as illustrated in FIG. 23C, an energy-curable resin 191 isfilled (dropped) into the through-holes 83 of the lower mold 181 and thesupport substrate 81W superimposed together. The lens resin portion 82is formed using the energy-curable resin 191. Thus, the energy-curableresin 191 is preferably subjected to a defoaming process in advance sothat bubbles are not included. A vacuum defoaming process or a defoamingprocess which uses centrifugal force is preferably performed as thedefoaming process. Moreover, the vacuum defoaming process is preferablyperformed after the filling. When the defoaming process is performed, itis possible to form the lens resin portion 82 without any bubbleincluded therein.

Subsequently, as illustrated in FIG. 23D, the upper mold 201 is disposedon the lower mold 181 and the support substrate 81W superimposedtogether. A plurality of concave optical transfer surfaces 202 isdisposed at a fixed interval in the upper mold 201, and similarly to thecase of disposing the lower mold 181, the upper mold 201 is disposedafter the through-holes 83 and the optical transfer surfaces 202 arealigned with high accuracy so that the centers thereof are identical inthe optical axis direction.

In a height direction which is the vertical direction on the drawingsurface, the position of the upper mold 201 is fixed so that theinterval between the upper mold 201 and the lower mold 181 reaches apredetermined distance with the aid of a controller that controls theinterval between the upper mold 201 and the lower mold 181. In thiscase, the space interposed between the optical transfer surface 202 ofthe upper mold 201 and the optical transfer surface 182 of the lowermold 181 is equal to the thickness of the lens resin portion 82 (thelens 21) calculated by optical design.

Alternatively, as illustrated in FIG. 23E, similarly to the case ofdisposing the lower mold 181, the planar surface 203 of the upper mold201 and the front planar portion 171 of the support substrate 81W may besuperimposed together. In this case, the distance between the upper mold201 and the lower mold 181 is the same as the thickness of the supportsubstrate 81W, and high-accuracy alignment can be realized in the planedirection and the height direction.

When the interval between the upper mold 201 and the lower mold 181 iscontrolled to reach a predetermined distance, in the above-describedstep of FIG. 23C, the amount of the energy-curable resin 191 droppedinto the through-holes 83 of the support substrate 81W is controlled tosuch an amount that the resin does not overflow the through-holes 83 ofthe support substrate 81W and the space surrounded by the upper mold 201and the lower mold 181 disposed on the upper and lower sides of thesupport substrate 81W. Due to this, it is possible to reduce themanufacturing cost without wasting the material of the energy-curableresin 191.

Subsequently, in the state illustrated in FIG. 23E, a process of curingthe energy-curable resin 191 is performed. The energy-curable resin 191is cured by being irradiated with heat or UV light as energy and beingleft for a predetermined period, for example. During curing, the uppermold 201 is pushed downward and is subjected to alignment, whereby adeformation resulting from shrinkage of the energy-curable resin 191 canbe suppressed as much as possible.

A thermoplastic resin may be used instead of the energy-curable resin191. In this case, in the state illustrated in FIG. 23E, the upper mold201 and the lower mold 181 are heated whereby the energy-curable resin191 is molded in a lens shape and is cured by being cooled.

Subsequently, as illustrated in FIG. 23F, the controller that controlsthe positions of the upper mold 201 and the lower mold 181 moves theupper mold 201 upward and the lower mold 181 downward so that the uppermold 201 and the lower mold 181 are separated from the support substrate81W. When the upper mold 201 and the lower mold 181 are separated fromthe support substrate 81W, the lens resin portion 82 including thelenses 21 is formed inside the through-holes 83 of the support substrate81W.

The surfaces of the upper mold 201 and the lower mold 181 that makecontact with the support substrate 81W may be coated with afluorine-based or silicon-based mold releasing agent. By doing so, thesupport substrate 81W can be easily separated from the upper mold 201and the lower mold 181. Moreover, various coatings such asfluorine-containing diamond-like carbon (DLC) may be performed as amethod of separating the support substrate 81W from the contact surfaceeasily.

Subsequently, as illustrated in FIG. 23G, the upper surface layer 122 isformed on the surface of the support substrate 81W and the lens resinportion 82, and the lower surface layer 123 is formed on the rearsurface of the support substrate 81W and the lens resin portion 82.Before or after the upper surface layer 122 and the lower surface layer123 are formed, chemical mechanical polishing (CMP) or the like may beperformed as necessary to planarize the front planar portion 171 and therear planar portion 172 of the support substrate 81W.

As described above, when the energy-curable resin 191 is pressure-molded(imprinted) into the through-holes 83 formed in the support substrate81W using the upper mold 201 and the lower mold 181, it is possible toform the lens resin portion 82 and to manufacture the substrate withlenses 41.

The shape of the optical transfer surface 182 and the optical transfersurface 202 is not limited to the concave shape described above but maybe determined appropriately according to the shape of the lens resinportion 82. As illustrated in FIG. 15, the lens shape of the substrateswith lenses 41 a to 41 e may take various shapes derived by opticaldesign. For example, the lens shape may have a biconvex shape, abiconcave shape, a plano-convex shape, a plano-concave shape, a convexmeniscus shape, a concave meniscus shape, or a high-order asphericalshape.

Moreover, the optical transfer surface 182 and the optical transfersurface 202 may have such a shape that the lens shape after forming hasa moth-eye structure.

According to the above-described manufacturing method, since a variationin the distance in the plane direction between the lens resin portions82 due to a curing shrinkage of the energy-curable resin 191 can beprevented by the interposed support substrate 81W, it is possible tocontrol the lens-to-lens distance with high accuracy. Moreover, themanufacturing method provides an effect of reinforcing the weakenergy-curable resin 191 with the strong support substrate 81W. Due tothis, the manufacturing method provides an advantage that it is possibleto provide the lens array substrate in which a plurality of lenseshaving good handling properties is disposed and to suppress a warp ofthe lens array substrate.

<Example in which Through-Hole has Polygonal Shape>

As illustrated in FIG. 19B, the planar shape of the through-hole 83 maybe polygonal such as rectangular.

FIG. 24 illustrates a plan view and cross-sectional views of the supportsubstrate 81 a and the lens resin portion 82 a of the substrate withlenses 41 a when the planar shape of the through-hole 83 is rectangular.

The cross-sectional views of the substrate with lenses 41 a illustratedin FIG. 24 are cross-sectional views taken along lines B-B′ and C-C′ inthe plan view.

As can be understood from comparison between the cross-sectional viewstaken along lines B-B′ and C-C′, when the through-hole 83 a isrectangular, the distance from the center of the through-hole 83 a to anupper outer edge of the through-hole 83 a and the distance from thecenter of the through-hole 83 a to a lower outer edge of thethrough-hole 83 a are different in the side direction and the diagonaldirection of the through-hole 83 a which is a rectangle, and thedistance in the diagonal direction is larger than that in the sidedirection. Due to this, when the planar shape of the through-hole 83 ais rectangular, if the lens portion 91 is circular, the distance fromthe outer circumference of the lens portion 91 to the side wall of thethrough-hole 83 a (that is, the length of the support portion 92) needsto be different in the side direction and the diagonal direction of therectangle.

Thus, the lens resin portion 82 a illustrated in FIG. 24 has thefollowing structures.

(1) The length of the arm portion 101 disposed on the outercircumference of the lens portion 91 is the same in the side directionand the diagonal direction of the rectangle.(2) The length of the leg portion 102 disposed on the outer side of thearm portion 101 to extend up to the side wall of the through-hole 83 ais set such that the length of the leg portion 102 in the diagonaldirection of the rectangle is larger than the length of the leg portion102 in the side direction of the rectangle.

As illustrated in FIG. 24, the leg portion 102 is not in direct-contactwith the lens portion 91, and the arm portion 101 is in direct-contactwith the lens portion 91.

In the lens resin portion 82 a illustrated in FIG. 24, the length andthe thickness of the arm portion 101 being in direct-contact with thelens portion 91 are constant over the entire outer circumference of thelens portion 91. Thus, it is possible to provide an effect or anadvantage that the entire lens portion 91 is supported with constantforce without deviation.

Further, when the entire lens portion 91 is supported with constantforce without deviation, it is possible to obtain an effect or anadvantage that, when stress is applied from the support substrate 81 asurrounding the through-holes 83 a to the entire outer circumference ofthe through-hole 83 a, for example, the stress is transmitted to theentire lens portion 91 without deviation whereby transmission of stressto a specific portion of the lens portion 91 in a deviated manner isprevented.

FIG. 25 illustrates a plan view and a cross-sectional view of thesupport substrate 81 a and the lens resin portion 82 a of the substratewith lenses 41 a, illustrating another example of the through-hole 83 ofwhich the planar shape is rectangular.

The cross-sectional views of the substrate with lenses 41 a illustratedin FIG. 25 are cross-sectional views taken along lines B-B′ and C-C′ inthe plan view.

In FIG. 25, similarly to FIGS. 22A and 22B, the distance from the centerof the through-hole 83 a to an upper outer edge of the through-hole 83 aand the distance from the center of the through-hole 83 a to a lowerouter edge of the through-hole 83 a are different in the side directionand the diagonal direction of the through-hole 83 a which is arectangle, and the distance in the diagonal direction is larger thanthat in the side direction. Due to this, when the planar shape of thethrough-hole 83 a is rectangular, if the lens portion 91 is circular,the distance from the outer circumference of the lens portion 91 to theside wall of the through-hole 83 a (that is, the length of the supportportion 92) needs to be different in the side direction and the diagonaldirection of the rectangle.

Thus, the lens resin portion 82 a illustrated in FIG. 25 has thefollowing structures.

(1) The length of the leg portion 102 disposed on the outercircumference of the lens portion 91 is constant along the four sides ofthe rectangle of the through-hole 83 a.(2) In order to realize the structure (1), the length of the arm portion101 is set such that the length of the arm portion in the diagonaldirection of the rectangle is larger than the length of the arm portionin the side direction of the rectangle.

As illustrated in FIG. 25, the thickness of the resin in the leg portion102 is larger than the thickness of the resin in the arm portion 101.Due to this, the volume of the leg portion 102 per unit area in theplane direction of the substrate with lenses 41 a is larger than thevolume of the arm portion 101.

In the embodiment of FIG. 25, when the volume of the leg portion 102 isdecreased as much as possible and is made constant along the four sidesof the rectangle of the through-hole 83 a, it is possible to provide aneffect or an advantage that, when a deformation such as swelling of aresin, for example, occurs, a change in the volume resulting from thedeformation is suppressed as much as possible and the change in thevolume does not deviate on the entire outer circumference of the lensportion 91 as much as possible.

FIG. 26 is a cross-sectional view illustrating another embodiment of thelens resin portion 82 and the through-hole 83 of the substrate withlenses 41.

The lens resin portion 82 and the through-hole 83 illustrated in FIG. 26have the following structures.

(1) The side wall of the through-hole 83 has a stair shape having astair portion 221.(2) The leg portion 102 of the support portion 92 of the lens resinportion 82 is disposed on the upper side of the side wall of thethrough-hole 83 and is also disposed on the stair portion 221 providedin the through-hole 83 so as to extend in the plane direction of thesubstrate with lenses 41.

A method of forming the stair-shaped through-hole 83 illustrated in FIG.26 will be described with reference to FIGS. 27A to 27F.

First, as illustrated in FIG. 27A, an etching stop film 241 havingresistance to the wet-etching when forming through-holes is formed onone surface of the support substrate 81W. The etching stop film 241 maybe a silicon nitride film, for example.

Subsequently, a hard mask 242 having resistance to the wet-etching whenforming through-holes is formed on the other surface of the supportsubstrate 81W. The hard mask 242 may also be a silicon nitride film, forexample.

Subsequently, as illustrated in FIG. 27B, a predetermined region of thehard mask 242 is opened to perform a first round of etching. In thefirst round of etching, a portion of the through-hole 83, which formsthe upper end of the stair portion 221 is etched. Due to this, theopening of the hard mask 242 for the first round of etching is a regioncorresponding to the opening, of the surface of the upper surface of thesubstrate with lenses 41 illustrated in FIG. 26.

Subsequently, as illustrated in FIG. 27C, wet-etching is performed sothat the support substrate 81W is etched to a predetermined depthaccording to the opening of the hard mask 242.

Subsequently, as illustrated in FIG. 27D, a hard mask 243 is formedagain on the surface of the etched support substrate 81W, and the hardmask 243 is opened in a region corresponding to the lower portion of thestair portion 221 of the through-hole 83. The second hard mask 243 mayalso be a silicon nitride film, for example.

Subsequently, as illustrated in FIG. 27E, wet-etching is performed sothat the support substrate 81W is etched to reach the etching stop film241 according to the opening of the hard mask 243.

Finally, as illustrated in FIG. 27F, the hard mask 243 on the uppersurface of the support substrate 81W and the etching stop film 241 onthe lower surface thereof are removed.

When wet-etching of the support substrate 81W for forming through-holesis performed in two rounds in the above-described manner, thethrough-hole 83 having the stair shape illustrated in FIG. 26 isobtained.

FIG. 28 illustrates a plan view and cross-sectional views of the supportsubstrate 81 a and the lens resin portion 82 a of the substrate withlenses 41 a when the through-hole 83 a has the stair portion 221 and theplanar shape of the through-hole 83 a is circular.

The cross-sectional views of the substrate with lenses 41 a in FIG. 28are cross-sectional views taken along lines B-B′ and C-C′ in the planview.

When the planar shape of the through-hole 83 a is circular, thecross-sectional shape of the through-hole 83 a is naturally the sameregardless of the diametrical direction. In addition to this, thecross-sectional shapes of the outer edge, the arm portion 101, and theleg portion 102 of the lens resin portion 82 a are the same regardlessof the diametrical direction.

The through-hole 83 a having the stair shape illustrated in FIG. 28provides an effect or an advantage that the area in which the legportion 102 of the support portion 92 of the lens resin portion 82 makescontact with the side wall of the through-hole 83 a can be increased ascompared to the through-hole 83 a illustrated in FIG. 14 in which thestair portion 221 is not provided in the through-hole 83 a. Due to this,it is possible to provide an effect or an advantage of increasing theadhesion strength between the lens resin portion 82 and the side wall ofthe through-hole 83 a (that is, the adhesion strength between the lensresin portion 82 a and the support substrate 81W).

FIG. 29 illustrates a plan view and cross-sectional views of the supportsubstrate 81 a and the lens resin portion 82 a of the substrate withlenses 41 a when the through-hole 83 a has the stair portion 221 and theplanar shape of the through-hole 83 a is rectangular.

The cross-sectional views of the substrate with lenses 41 a in FIG. 29are cross-sectional views taken along lines B-B′ and C-C′ in the planview.

The lens resin portion 82 and the through-hole 83 illustrated in FIG. 29have the following structures.

(1) The length of the arm portion 101 disposed on the outercircumference of the lens portion 91 is the same in the side directionand the diagonal direction of the rectangle.(2) The length of the leg portion 102 disposed on the outer side of thearm portion 101 to extend up to the side wall of the through-hole 83 ais set such that the length of the leg portion 102 in the diagonaldirection of the rectangle is larger than the length of the leg portion102 in the side direction of the rectangle.

As illustrated in FIG. 29, the leg portion 102 is not in direct-contactwith the lens portion 91 whereas the arm portion 101 is indirect-contact with the lens portion 91.

In the lens resin portion 82 a illustrated in FIG. 29, similarly to thelens resin portion 82 a illustrated in FIG. 24, the length and thethickness of the arm portion 101 being in direct-contact with the lensportion 91 are constant over the entire outer circumference of the lensportion 91. Due to this, it is possible to provide an effect or anadvantage that the entire lens portion 91 is supported with constantforce without deviation.

Further, when the entire lens portion 91 is supported with constantforce without deviation, it is possible to obtain an effect or anadvantage that, when stress is applied from the support substrate 81 asurrounding the through-holes 83 a to the entire outer circumference ofthe through-hole 83 a, for example, the stress is transmitted to theentire lens portion 91 without deviation whereby transmission of stressto a specific portion of the lens portion 91 in a deviated manner isprevented.

Further, the structure of the through-hole 83 a illustrated in FIG. 29provides an effect or an advantage that the area in which the legportion 102 of the support portion 92 of the lens resin portion 82 amakes contact with the side wall of the through-hole 83 a can beincreased as compared to the through-hole 83 a illustrated in FIG. 24and the like in which the stair portion 221 is not provided in thethrough-hole 83 a. Due to this, it is possible to provide an effect oran advantage of increasing the adhesion strength between the lens resinportion 82 a and the side wall of the through-hole 83 a (that is, theadhesion strength between the lens resin portion 82 a and the supportsubstrate 81 a).

11. Direct Bonding of Substrates with Lenses

Next, direct bonding of the substrates with lenses 41W in the substratestate in which the plurality of substrates with lenses 41 is formed willbe described.

In the following description, as illustrated in FIGS. 30A and 30B, thesubstrate with lenses 41W in the substrate state in which the pluralityof substrates with lenses 41 a is formed will be referred to as asubstrate with lenses 41W-a, and the substrate with lenses 41W in thesubstrate state in which the plurality of substrates with lenses 41 b isformed will be referred to as a substrate with lenses 41W-b. The othersubstrates with lenses 41 c to 41 e are similarly referred to.

Direct bonding between the substrate with lenses 41W-a in the substratestate and the substrate with lenses 41W-b in the substrate state will bedescribed with reference to FIGS. 31A and 31B.

In FIGS. 31A and 31B, the portions of the substrate with lenses 41W-bcorresponding to the respective portions of the substrate with lenses41W-a will be denoted by the same reference numerals as those of thesubstrate with lenses 41W-a.

The upper surface layer 122 or 125 are formed on the upper surface ofthe substrates with lenses 41W-a and 41W-b. The lower surface layer 123or 124 is formed on the lower surface of the substrates with lenses41W-a and 41W-b. Moreover, as illustrated in FIG. 31A, a plasmaactivation process is performed on the entire lower surface includingthe rear planar portion 172 of the substrate with lenses 41W-a and theentire upper surface including the front planar portion 171 of thesubstrate with lenses 41W-b, serving as the bonding surfaces of thesubstrates with lenses 41W-a and 41W-b. The gas used in the plasmaactivation process may be arbitrary gas which can be plasma-processedsuch as O₂, N₂, He, Ar, or H₂. However, it is desirable that the samegas as the constituent elements of the upper surface layer 122 and thelower surface layer 123 is used as the gas used in the plasma activationprocess. By doing so, degeneration of the film itself of the uppersurface layer 122 and the lower surface layer 123 can be suppressed.

As illustrated in FIG. 31B, the rear planar portion 172 of the substratewith lenses 41W-a in the activated surface state and the front planarportion 171 of the substrate with lenses 41W-b are attached together.

With the attachment process of the substrates with lenses, a hydrogenbond is formed between the hydrogen of the OH radical on the surface ofthe lower surface layer 123 or 124 of the substrate with lenses 41W-aand the hydrogen of the OH radical on the surface of the upper surfacelayer 122 or 125 of the substrate with lenses 41W-b. Due to this, thesubstrates with lenses 41W-a and 41W-b are fixed together. Theattachment process of the substrates with lenses can be performed underthe condition of the atmospheric pressure.

An annealing process is performed on the attached substrates with lenses41W-a and 41W-b. In this way, dehydration condensation occurs from thestate in which the OH radicals form a hydrogen bond, and an oxygen-basedcovalent bond is formed between the lower surface layer 123 or 124 ofthe substrate with lenses 41W-a and the upper surface layer 122 or 125of the substrate with lenses 41W-b. Alternatively, the element containedin the lower surface layer 123 or 124 of the substrate with lenses 41W-aand the element contained in the upper surface layer 122 or 125 of thesubstrate with lenses 41W-b form a covalent bond. By these bonds, thetwo substrates with lenses are strongly fixed together. A state in whicha covalent bond is formed between the lower surface layer 123 or 124 ofthe substrate with lenses 41W disposed on the upper side and the uppersurface layer 122 or 125 of the substrate with lenses 41W disposed onthe lower side whereby the two substrates with lenses 41W are fixedtogether is referred to as direct bonding in the present specification.The method of fixing a plurality of substrates with lenses by the resinformed on the entire surface, disclosed in Patent Literature 1 has aproblem that the resin may experience curing shrinkage and thermalexpansion and the lens may be deformed. In contrast, the direct bondingof the present technique provides an effect or an advantage that, sincethe resin is not used when fixing the plurality of substrates withlenses 41W, the plurality of substrates with lenses 41W can be fixedwithout causing a curing shrinkage and a thermal expansion.

The annealing process can be performed under the condition of theatmospheric pressure. This annealing process can be performed at atemperature of 100° C. or higher, 150° C. or higher, or 200° C. orhigher in order to realize dehydration condensation. On the other hand,this annealing process can be performed at a temperature of 400° C. orlower, 350° C. or lower, or 300° C. or lower from the perspective ofprotecting the energy-curable resin 191 for forming the lens resinportion 82 from heat and the perspective of suppressing degassing fromthe energy-curable resin 191.

If the attachment process of the substrates with lenses 41W or thedirect bonding process of the substrates with lenses 41W is performedunder the condition of the atmospheric pressure, when the bondedsubstrates with lenses 41W-a and 41W-b are returned to the environmentof the atmospheric pressure, a pressure difference occurs between theoutside of the lens resin portion 82 and the space between the bondedlens resin portions 82. Due to this pressure difference, pressure isapplied to the lens resin portion 82 and the lens resin portion 82 maybe deformed.

When both the attachment process of the substrates with lenses 41W andthe direct bonding process of the substrates with lenses are performedunder the condition of the atmospheric pressure, it is possible toprovide an effect or an advantage that the deformation of the lens resinportion 82 which may occur when the bonding was performed under thecondition other than the atmospheric pressure can be avoided.

When the substrate subjected to the plasma activation process isdirect-bonded (that is, plasma-bonded), since such fluidity and thermalexpansion as when a resin is used as an adhesive can be suppressed, itis possible to improve the positional accuracy when the substrates withlenses 41W-a and 41W-b are bonded.

As described above, the upper surface layer 122 or the lower surfacelayer 123 is formed on the rear planar portion 172 of the substrate withlenses 41W-a and the front planar portion 171 of the substrate withlenses 41W-b. In the upper surface layer 122 and the lower surface layer123, a dangling bond is likely to be formed due to the plasma activationprocess performed previously. That is, the lower surface layer 123formed on the rear planar portion 172 of the substrate with lenses 41W-aand the upper surface layer 122 formed on the front planar portion 171of the substrate with lenses 41W-a also have the function of increasingthe bonding strength.

Moreover, when the upper surface layer 122 or the lower surface layer123 is formed of an oxide film, since the layer is not affected by achange in the film property due to plasma (O₂), it is possible toprovide an effect of suppressing plasma-based corrosion of the lensresin portion 82.

As described above, the substrate with lenses 41W-a in the substratestate in which the plurality of substrates with lenses 41 a is formedand the substrate with lenses 41W-b in the substrate state in which theplurality of substrates with lenses 41 b is formed are direct-bondedafter being subjected to a plasma-based surface activation process (thatis, the substrates are bonded using plasma bonding).

FIGS. 32A to 32F illustrate a first stacking method of stacking fivesubstrates with lenses 41 a to 41 e corresponding to the stacked lensstructure 11 illustrated in FIG. 13 in the substrate state using themethod of bonding the substrates with lenses 41W in the substrate statedescribed with reference to FIGS. 31A and 31B.

First, as illustrated in FIG. 32A, a substrate with lenses 41W-e in thesubstrate state positioned on the bottom layer of the stacked lensstructure 11 is prepared.

Subsequently, as illustrated in FIG. 32B, a substrate with lenses 41W-din the substrate state positioned on the second layer from the bottom ofthe stacked lens structure 11 is bonded to the substrate with lenses41W-e in the substrate state.

Subsequently, as illustrated in FIG. 32C, a substrate with lenses 41W-cin the substrate state positioned on the third layer from the bottom ofthe stacked lens structure 11 is bonded to the substrate with lenses41W-d in the substrate state.

Subsequently, as illustrated in FIG. 32D, a substrate with lenses 41W-bin the substrate state positioned on the fourth layer from the bottom ofthe stacked lens structure 11 is bonded to the substrate with lenses41W-c in the substrate state.

Subsequently, as illustrated in FIG. 32E, a substrate with lenses 41W-ain the substrate state positioned on the fifth layer from the bottom ofthe stacked lens structure 11 is bonded to the substrate with lenses41W-b in the substrate state.

Finally, as illustrated in FIG. 32F, a diaphragm plate 51W positioned onthe upper layer of the substrate with lenses 41 a of the stacked lensstructure 11 is bonded to the substrate with lenses 41W-a in thesubstrate state.

In this way, when the five substrates with lenses 41W-a to 41W-e in thesubstrate state are sequentially stacked one by one in the order fromthe substrate with lenses 41W on the lower layer of the stacked lensstructure 11 to the substrate with lenses 41W on the upper layer, thestacked lens structure 11W in the substrate state is obtained.

FIGS. 33A to 33F illustrate a second stacking method of stacking fivesubstrates with lenses 41 a to 41 e corresponding to the stacked lensstructure 11 illustrated in FIG. 13 in the substrate state using themethod of bonding the substrates with lenses 41W in the substrate statedescribed with reference to FIGS. 31A and 31B.

First, as illustrated in FIG. 33A, a diaphragm plate 51W positioned onthe upper layer of the substrate with lenses 41 a of the stacked lensstructure 11 is prepared.

Subsequently, as illustrated in FIG. 33B, a substrate with lenses 41W-ain the substrate state positioned on the top layer of the stacked lensstructure 11 is inverted upside down and is then bonded to the diaphragmplate 51W.

Subsequently, as illustrated in FIG. 33C, a substrate with lenses 41W-bin the substrate state positioned on the second layer from the top ofthe stacked lens structure 11 is inverted upside down and is then bondedto the substrate with lenses 41W-a in the substrate state.

Subsequently, as illustrated in FIG. 33D, a substrate with lenses 41W-cin the substrate state positioned on the third layer from the top of thestacked lens structure 11 is inverted upside down and is then bonded tothe substrate with lenses 41W-b in the substrate state.

Subsequently, as illustrated in FIG. 33E, a substrate with lenses 41W-din the substrate state positioned on the fourth layer from the top ofthe stacked lens structure 11 is inverted upside down and is then bondedto the substrate with lenses 41W-c in the substrate state.

Finally, as illustrated in FIG. 33F, a substrate with lenses 41W-e inthe substrate state positioned on the fifth layer from the top of thestacked lens structure 11 is inverted upside down and is then bonded tothe substrate with lenses 41W-d in the substrate state.

In this way, when the five substrates with lenses 41W-a to 41W-e in thesubstrate state are sequentially stacked one by one in the order fromthe substrate with lenses 41W on the upper layer of the stacked lensstructure 11 to the substrate with lenses 41W on the lower layer, thestacked lens structure 11W in the substrate state is obtained.

The five substrates with lenses 41W-a to 41W-e in the substrate statestacked by the stacking method described in FIGS. 32A to 32F or FIGS.33A to 33F are divided in respective modules or chips using a blade, alaser, or the like whereby the stacked lens structure 11 in which thefive substrates with lenses 41 a to 41 e are stacked is obtained.

12. Eighth and Ninth Embodiments of Camera Module

FIG. 34 is a diagram illustrating an eighth embodiment of a cameramodule which uses a stacked lens structure to which the presenttechnique is applied.

FIG. 35 is a diagram illustrating a ninth embodiment of a camera modulewhich uses a stacked lens structure to which the present technique isapplied.

In description of FIGS. 34 and 35, only the portions different fromthose of the camera module E illustrated in FIG. 13 will be described.

In a camera module 1H illustrated in FIG. 34 and a camera module 1Jillustrated in FIG. 35, the portion of the structure material 73 of thecamera module E illustrated in FIG. 13 is replaced with anotherstructure.

In the camera module 1H illustrated in FIG. 34, the portion of thestructure material 73 of the camera module 1J is replaced with structurematerials 301 a and 301 b and a light transmitting substrate 302.

Specifically, the structure material 301 a is disposed in a portion ofthe upper side of the light receiving element 12. The light receivingelement 12 and the light transmitting substrate 302 are fixed by thestructure material 301 a. The structure material 301 a is an epoxy-basedresin, for example.

The structure material 301 b is disposed on the upper side of the lighttransmitting substrate 302. The light transmitting substrate 302 and thestacked lens structure 11 are fixed by the structure material 301 b. Thestructure material 301 b is an epoxy-based resin, for example.

In contrast, in the camera module 1J illustrated in FIG. 35, the portionof the structure material 301 a of the camera module 1H illustrated inFIG. 34 is replaced with a resin layer 311 having a light transmittingproperty.

The resin layer 311 is disposed on the entire upper surface of the lightreceiving element 12. The light receiving element 12 and the lighttransmitting substrate 302 are fixed by the resin layer 311. The resinlayer 311 disposed on the entire upper surface of the light receivingelement 12 provides an effect or an advantage that, when stress isapplied to the light transmitting substrate 302 from the upper side ofthe light transmitting substrate 302, the resin layer 311 prevents thestress from concentrating on a partial region of the light receivingelement 12 so that the stress is received while being distributed to theentire surface of the light receiving element 12.

The structure material 301 b is disposed on the upper side of the lighttransmitting substrate 302. The light transmitting substrate 302 and thestacked lens structure 11 are fixed by the structure material 301 b.

The camera module 1H illustrated in FIG. 34 and the camera module 1Jillustrated in FIG. 35 include the light transmitting substrate 302 onthe upper side of the light receiving element 12. The light transmittingsubstrate 302 provides an effect or an advantage of suppressing thelight receiving element 12 from being damaged in the course ofmanufacturing the camera module 1H or 1J, for example.

13. Tenth Embodiment of Camera Module

FIG. 36 is a diagram illustrating a tenth embodiment of a camera modulewhich uses a stacked lens structure to which the present technique isapplied.

In the camera module 1J illustrated in FIG. 36, the stacked lensstructure 11 is accommodated in a lens barrel 74. The lens barrel 74 isfixed to a moving member 332 moving along a shaft 331 by a fixing member333. When the lens barrel 74 is moved in an axial direction of the shaft331 by a drive motor (not illustrated), the distance from the stackedlens structure 11 to the imaging surface of the light receiving element12 is adjusted.

The lens barrel 74, the shaft 331, the moving member 332, and the fixingmember 333 are accommodated in the housing 334. A protective substrate335 is disposed on an upper portion of the light receiving element 12,and the protective substrate 335 and the housing 334 are connected by anadhesive 336.

The mechanism that moves the stacked lens structure 11 provides aneffect or an advantage of allowing a camera which uses the camera module1J to perform an auto-focus operation when photographing an image.

14. Eleventh Embodiment of Camera Module

FIG. 37 is a diagram illustrating an eleventh embodiment of a cameramodule which uses a stacked lens structure to which the presenttechnique is applied.

A camera module 1L illustrated in FIG. 37 is a camera module in which afocus adjustment mechanism based on a piezoelectric element is added.

That is, in the camera module 1L, a structure material 301 a is disposedin a portion of the upper side of the light receiving element 12similarly to the camera module 1H illustrated in FIG. 34. The lightreceiving element 12 and the light transmitting substrate 302 are fixedby the structure material 301 a. The structure material 301 a is anepoxy-based resin, for example.

A piezoelectric element 351 is disposed on an upper side of the lighttransmitting substrate 302. The light transmitting substrate 302 and thestacked lens structure 11 are fixed by the piezoelectric element 351.

In the camera module 1L, when a voltage is applied to the piezoelectricelement 351 disposed on the lower side of the stacked lens structure 11and the voltage is blocked, the stacked lens structure 11 can be movedup and down. The means for moving the stacked lens structure 11 is notlimited to the piezoelectric element 351, but another device of whichthe shape changes when a voltage is applied or blocked can be used. Forexample, a MEMS device can be used.

The mechanism that moves the stacked lens structure 11 provides aneffect or an advantage of allowing a camera which uses the camera module1L to perform an auto-focus operation when photographing an image.

15. Advantage of Present Structure Compared to Other Structures

The stacked lens structure 11 has a structure (hereinafter referred toas a present structure) in which the substrates with lenses 41 are fixedby direct bonding. The effect and the advantage of the present structurewill be described in comparison with other structures of a substratewith lenses in which lenses are formed.

Comparative Structure Example 1

FIG. 38 is a cross-sectional view of a first substrate structure(hereinafter referred to as Comparative Structure Example 1) forcomparing with the present structure and is a cross-sectional view of awafer-level stacked structure disclosed in FIG. 14B of JP 2011-138089 A(hereinafter referred to as Comparative Literature 1).

A wafer-level stacked structure 1000 illustrated in FIG. 38 has astructure in which two lens array substrates 1021 are stacked on asensor array substrate 1012 in which a plurality of image sensors 1011is arranged on a wafer substrate 1010 with a columnar spacer 1022interposed. Each lens array substrate 1021 includes a substrate withlenses 1031 and lenses 1032 formed in a plurality of through-holeportions formed in the substrate with lenses 1031.

Comparative Structure Example 2

FIG. 39 is a cross-sectional view of a second substrate structure(hereinafter referred to as Comparative Structure Example 2) forcomparing with the present structure and is a cross-sectional view of alens array substrate disclosed in FIG. 5A of JP 2009-279790 A(hereinafter referred to as Comparative Literature 2).

In a lens array substrate 1041 illustrated in FIG. 39, lenses 1053 areprovided in a plurality of through-holes 1052 formed in a planarsubstrate 1051. Each lens 1053 is formed of a resin (energy-curableresin) 1054, and the resin 1054 is also formed on the upper surface ofthe substrate 1051.

A method of manufacturing the lens array substrate 1041 illustrated inFIG. 39 will be described briefly with reference to FIGS. 40A to 40C.

FIG. 40A illustrates a state in which the substrate 1051 in which theplurality of through-holes 1052 is formed is placed on a lower mold1061. The lower mold 1061 is a metal mold that presses the resin 1054toward the upper side from the lower side in a subsequent step.

FIG. 40B illustrates a state in which, after the resin 1054 is appliedto the inside of the plurality of through-holes 1052 and the uppersurface of the substrate 1051, the upper mold 1062 is disposed on thesubstrate 1051 and pressure-molding is performed using the upper mold1062 the lower mold 1061. The upper mold 1062 is a metal mold thatpresses the resin 1054 toward the lower side from the upper side. In astate illustrated in FIG. 40B, the resin 1054 is cured.

FIG. 40C illustrates a state in which, after the resin 1054 is cured,the upper mold 1062 and the lower mold 1061 are removed and the lensarray substrate 1041 is obtained.

The lens array substrate 1041 is characterized in that (1) the resin1054 formed at the positions of the through-holes 1052 of the substrate1051 forms the lenses 1053 whereby a plurality of lenses 1053 is formedin the substrate 1051 and (2) a thin layer of the resin 1054 is formedon the entire upper surface of the substrate 1051 positioned between theplurality of lenses 1053.

When a plurality of lens array substrates 1041 is stacked to form astructure, it is possible to obtain an effect or an advantage that thethin layer of the resin 1054 formed on the entire upper surface of thesubstrate 1051 functions as an adhesive that attaches the substrates.

Moreover, when the plurality of lens array substrates 1041 is stacked toform a structure, since the area of attaching the substrates can beincreased as compared to the wafer-level stacked structure 1000illustrated in FIG. 38 as Comparative Structure Example 1, thesubstrates can be attached with stronger force.

Effect of Resin in Comparative Structure Example 2

In Comparative Literature 2 which discloses the lens array substrate1041 illustrated in FIG. 39 as Comparative Structure Example 2, it isdescribed that the resin 1054 serving as the lenses 1053 provides thefollowing effects.

In Comparative Structure Example 2, an energy-curable resin is used asthe resin 1054. Moreover, a photo-curable resin is used as an example ofthe energy-curable resin. When a photo-curable resin is used as theenergy-curable resin and the resin 1054 is irradiated with UV light, theresin 1054 is cured. With this curing, a curing shrinkage occurs in theresin 1054.

However, according to the structure of the lens array substrate 1041illustrated in FIG. 39, even when a curing shrinkage of the resin 1054occurs, since the substrate 1051 is interposed between the plurality oflenses 1053, it is possible to prevent a variation in the distancebetween the lenses 1053 resulting from a curing shrinkage of the resin1054. As a result, it is possible to suppress a warp of the lens arraysubstrate 1041 in which the plurality of lenses 1053 is disposed.

Comparative Structure Example 3

FIG. 41 is a cross-sectional view of a third substrate structure(hereinafter referred to as Comparative Structure Example 3) forcomparing with the present structure and is a cross-sectional view of alens array substrate disclosed in FIG. 1 of JP 2010-256563 A(hereinafter referred to as Comparative Document 3).

In a lens array substrate 1081 illustrated in FIG. 41, lenses 1093 areprovided in a plurality of through-holes 1092 formed in a planarsubstrate 1091. Each lens 1093 is formed of a resin (energy-curableresin) 1094, and the resin 1094 is also formed on the upper surface ofthe substrate 1091 in which the through-hole 1092 is not formed.

A method of manufacturing the lens array substrate 1081 illustrated inFIG. 41 will be described briefly with reference to FIGS. 42A to 42C.

FIG. 42A illustrates a state in which the substrate 1091 in which theplurality of through-holes 1092 is formed is placed on a lower mold1101. The lower mold 1101 is a metal mold that presses the resin 1094toward the upper side from the lower side in a subsequent step.

FIG. 42B illustrates a state in which, after the resin 1094 is appliedto the inside of the plurality of through-holes 1092 and the uppersurface of the substrate 1091, an upper mold 1102 is disposed on thesubstrate 1091 and pressure-molding is performed using the upper mold1102 and the lower mold 1101. The upper mold 1102 is a metal mold thatpresses the resin 1094 toward the lower side from the upper side. In thestate illustrated in FIG. 42B, the resin 1094 is cured.

FIG. 42C illustrates a state in which, after the resin 1094 is cured,the upper mold 1102 and the lower mold 1101 are removed to obtain thelens array substrate 1081.

The lens array substrate 1081 is characterized in that (1) the resin1094 formed at the positions of the through-holes 1092 of the substrate1091 forms the lenses 1093 whereby a plurality of lenses 1093 is formedin the substrate 1091 and (2) a thin layer of the resin 1094 is formedon the entire upper surface of the substrate 1091 positioned between theplurality of lenses 1093.

Effect of Resin in Comparative Structure Example 3

In Comparative Literature 3 which discloses the lens array substrate1081 illustrated in FIG. 41 as Comparative Structure Example 3, it isdescribed that the resin 1094 serving as the lenses 1093 provides thefollowing effects.

In Comparative Structure Example 3, an energy-curable resin is used asthe resin 1094. Moreover, a photo-curable resin is used as an example ofthe energy-curable resin. When a photo-curable resin is used as theenergy-curable resin and the resin 1094 is irradiated with UV light, theresin 1094 is cured. With this curing, a curing shrinkage occurs in theresin 1094.

However, according to the structure of the lens array substrate 1081illustrated in FIG. 41, even when a curing shrinkage of the resin 1094occurs, since the substrate 1091 is interposed between the plurality oflenses 1093, it is possible to prevent a variation in the distancebetween the lenses 1093 resulting from a curing shrinkage of the resin1094. As a result, it is possible to suppress a warp of the lens arraysubstrate 1081 in which the plurality of lenses 1093 is disposed.

As described above, in Comparative Literature 2 and 3, it is describedthat a curing shrinkage occurs when a photo-curable resin is cured. Thecuring shrinkage occurring when a photo-curable resin is cured is alsodisclosed in JP 2013-1091 A or the like as well as ComparativeLiterature 2 and 3.

Moreover, the problem of a curing shrinkage occurring in a resin whenthe resin is molded into the shape of lenses and the molded resin iscured is not limited to the photo-curable resin. For example, a curingshrinkage occurring during curing is also a problem in a heat-curableresin which is one type of an energy-curable resin similarly to thephoto-curable resin. This is also disclosed in JP 2010-204631 A or thelike as well as Comparative Literature 1 and 3, for example.

Comparative Structure Example 4

FIG. 43 is a cross-sectional view of a fourth substrate structure(hereinafter referred to as Comparative Structure Example 4) forcomparing with the present structure and is a cross-sectional view of alens array substrate disclosed in FIG. 6 of Comparative Literature 2described above.

A lens array substrate 1121 illustrated in FIG. 43 is different from thelens array substrate 1041 illustrated in FIG. 39 in that the shape of asubstrate 1141 other than the through-holes 1042 protrudes toward thelower side as well as the upper side and a resin 1144 is also formed ina portion of the lower surface of the substrate 1141. The otherconfigurations of the lens array substrate 1121 are the same as those ofthe lens array substrate 1041 illustrated in FIG. 39.

FIG. 44 is a diagram illustrating a method of manufacturing the lensarray substrate 1121 illustrated in FIG. 43 and is a diagramcorresponding to FIG. 40B.

FIG. 44 illustrates a state in which, after the resin 1144 is applied tothe inside of the plurality of through-holes 1142 and the upper surfaceof the substrate 1141, pressure-molding is performed using an upper mold1152 and a lower mold 1151. The resin 1144 is also injected between thelower surface of the substrate 1141 and the lower mold 1151. In thestate illustrated in FIG. 44, the resin 1144 is cured.

The lens array substrate 1121 is characterized in that (1) the resin1144 formed at the positions of the through-holes 1142 of the substrate1141 forms the lenses 1143 whereby a plurality of lenses 1143 is formedin the substrate 1141 and (2) a thin layer of the resin 1144 is formedon the entire upper surface of the substrate 1141 positioned between theplurality of lenses 1143 and a thin layer of the resin 1144 is alsoformed in a portion of the lower surface of the substrate 1141.

Effect of Resin in Comparative Structure Example 4

In Comparative Literature 2 which discloses the lens array substrate1121 illustrated in FIG. 43 as Comparative Structure Example 4, it isdescribed that the resin 1144 serving as the lenses 1143 provides thefollowing effects.

In the lens array substrate 1121 illustrated in FIG. 43, which isComparative Structure Example 4, a photo-curable resin which is anexample of an energy-curable resin is used as the resin 1144. When theresin 1144 is irradiated with UV light, the resin 1144 is cured. Withthis curing, a curing shrinkage occurs in the resin 1144 similarly toComparative Structure Examples 2 and 3.

However, in the lens array substrate 1121 of Comparative StructureExample 4, a thin layer of the resin 1144 is formed in a certain regionof the lower surface of the substrate 1141 as well as the entire uppersurface of the substrate 1141 positioned between the plurality of lenses1143.

In this way, when a structure in which the resin 1144 is formed on boththe upper surface and the lower surface of the substrate 1141 is used,it is possible to cancel the direction of a warp of the entire lensarray substrate 1121.

In contrast, in the lens array substrate 1041 illustrated in FIG. 39 asComparative Structure Example 2, although a thin layer of the resin 1054is formed on the entire upper surface of the substrate 1051 positionedbetween the plurality of lenses 1053, a thin layer of the resin 1054 isnot formed on the lower surface of the substrate 1051.

Thus, in the lens array substrate 1121 illustrated in FIG. 43, it ispossible to provide a lens array substrate in which the amount of a warpis reduced as compared to the lens array substrate 1041 illustrated inFIG. 39.

Comparative Structure Example 5

FIG. 45 is a cross-sectional view of a fifth substrate structure(hereinafter referred to as Comparative Structure Example 5) forcomparing with the present structure and is a cross-sectional view of alens array substrate disclosed in FIG. 9 of Comparative Literature 2described above.

A lens array substrate 1161 illustrated in FIG. 45 is different from thelens array substrate 1041 illustrated in FIG. 39 in that a resinprotrusion region 1175 is formed on a rear surface of a substrate 1171near through-holes 1172 formed in the substrate 1171. The otherconfigurations of the lens array substrate 1161 are the same as those ofthe lens array substrate 1041 illustrated in FIG. 39.

FIG. 45 illustrates the divided lens array substrate 1161.

The lens array substrate 1161 is characterized in that (1) a resin 1174formed at the positions of the through-holes 1172 of the substrate 1171forms lenses 1173 whereby a plurality of lenses 1173 is formed in thesubstrate 1171 and (2) a thin layer of the resin 1174 is formed on theentire upper surface of the substrate 1171 positioned between theplurality of lenses 1173 and a thin layer of the resin 1174 is alsoformed in a portion of the lower surface of the substrate 1171.

Effect of Resin in Comparative Structure Example 5

In Comparative Literature 2 which discloses the lens array substrate1161 illustrated in FIG. 45 as Comparative Structure Example 5, it isdescribed that the resin 1174 serving as the lenses 1173 provides thefollowing effects.

In the lens array substrate 1161 illustrated in FIG. 45, which isComparative Structure Example 5, a photo-curable resin which is anexample of an energy-curable resin is used as the resin 1174. When theresin 1174 is irradiated with UV light, the resin 1174 is cured. Withthis curing, a curing shrinkage occurs in the resin 1174 similarly toComparative Structure Examples 2 and 3.

However, in the lens array substrate 1171 of Comparative StructureExample 5, a thin layer (the resin protrusion region 1175) of the resin1174 is formed in a certain region of the lower surface of the substrate1171 as well as the entire upper surface of the substrate 1171positioned between the plurality of lenses 1173. Due to this, it ispossible to provide a lens array substrate in which the direction of awarp of the entire lens array substrate 1171 is canceled and the amountof a warp is reduced.

Comparison of Effects of Resin in Comparative Structure Examples 2 to 5

The effects of the resin in Comparative Structure Examples 2 to 5 can besummarized as below.

(1) As in Comparative Structure Examples 2 and 3, in the case of thestructure in which a resin layer is disposed on the entire upper surfaceof a lens array substrate, a warp occurs in the substrate in which theplurality of lenses is disposed.

FIGS. 46A to 46C are diagrams schematically illustrating a structure inwhich a resin layer is disposed on the entire upper surface of a lensarray substrate and are diagrams illustrating the effect of the resinserving as lenses.

As illustrated in FIGS. 46A and 46B, a curing shrinkage occurs in thelayer of a photo-curable resin 1212 disposed on the upper surface of alens array substrate 1211 (lenses and through-holes are not illustrated)when irradiated with UV light for curing. As a result, force in theshrinking direction resulting from the photo-curable resin 1212 occursin the layer of the photo-curable resin 1212.

On the other hand, the lens array substrate 1211 itself does not shrinkor expand even when irradiated with UV light. That is, force resultingfrom the substrate does not occur in the lens array substrate 1211itself. As a result, the lens array substrate 1211 warps in a downwardconvex shape as illustrated in FIG. 46C.

(2) However, as in Comparative Structure Examples 4 and 5, in the caseof a structure in which a resin layer is disposed on both the uppersurface and the lower surface of a lens array substrate, since thedirection of a warp of the lens array substrate is canceled, it ispossible to reduce the amount of a warp of the lens array substrate ascompared to Comparative Structure Examples 2 and 3.

FIGS. 47A to 47C are diagrams schematically illustrating a structure inwhich a resin layer is disposed on both the upper surface and the lowersurface of a lens array substrate and is a diagram illustrating theeffect of the resin serving as lenses.

As illustrated in FIGS. 47A and 47B, a curing shrinkage occurs in thelayer of a photo-curable resin 1212 disposed on the upper surface of alens array substrate 1211 when irradiated with UV light for curing. As aresult, force in the shrinking direction resulting from thephoto-curable resin 1212 occurs in the layer of the photo-curable resin1212 disposed on the upper surface of the lens array substrate 1211. Dueto this, force that warps the lens array substrate 1211 in a downwardconvex shape acts on the upper surface side of the lens array substrate1211.

In contrast, the lens array substrate 1211 itself does not shrink orexpand even when irradiated with UV light. That is, force resulting fromthe substrate does not occur in the lens array substrate 1211 itself.

On the other hand, a curing shrinkage occurs in the layer of thephoto-curable resin 1212 disposed on the lower surface of the lens arraysubstrate 1211 when irradiated with UV light for curing. As a result,force in the shrinking direction resulting from the photo-curable resin1212 occurs in the layer of the photo-curable resin 1212 disposed on thelower surface of the lens array substrate 1211. Due to this, force thatwarps the lens array substrate 1211 in an upward convex shape acts onthe lower surface side of the lens array substrate 1211.

The force that warps the lens array substrate 1211 in a downward convexshape, acting on the upper surface side of the lens array substrate 1211and the force that warps the lens array substrate 1211 in an upwardconvex shape, acting on the lower surface side of the lens arraysubstrate 1211 cancel each other.

As a result, as illustrated in FIG. 47C, the amount of a warp of thelens array substrate 1211 in Comparative Structure Examples 4 and 5 issmaller than the amount of a warp in Comparative Structure Examples 2and 3 illustrated in FIG. 46C.

As described above, the force that warps the lens array substrate andthe amount of a warp of the lens array substrate are affected by arelative relation between (1) the direction and the magnitude of theforce acting on the lens array substrate on the upper surface of thelens array substrate and (2) the direction and the magnitude of theforce acting on the lens array substrate on the lower surface of thelens array substrate.

Comparative Structure Example 6

Thus, for example, as illustrated in FIG. 48A, a lens array substratestructure in which the layer and the area of the photo-curable resin1212 disposed on the upper surface of the lens array substrate 1211 arethe same as the layer and the area of the photo-curable resin 1212disposed on the lower surface of the lens array substrate 1211 can beconsidered. This lens array substrate structure will be referred to as asixth substrate structure (hereinafter referred to as ComparativeStructure Example 6) for comparison with the present structure.

In Comparative Structure Example 6, force in a shrinking directionresulting from the photo-curable resin 1212 occurs in the layer of thephoto-curable resin 1212 disposed on the upper surface of the lens arraysubstrate 1211. Force resulting from the substrate does not occur in thelens array substrate 1211 itself. Due to this, force that warps the lensarray substrate 1211 in a downward convex shape acts on the uppersurface side of the lens array substrate 1211.

On the other hand, force in a shrinking direction resulting from thephoto-curable resin 1212 occurs in the layer of the photo-curable resin1212 disposed on the lower surface of the lens array substrate 1211.Force resulting from the substrate does not occur in the lens arraysubstrate 1211 itself. Due to this, force that warps the lens arraysubstrate 1211 in an upward convex shape acts on the lower surface sideof the lens array substrate 1211.

The two types of force that warps the lens array substrate 1211 act inthe direction of canceling each other more effectively than thestructure illustrated in FIG. 47A. As a result, the force that warps thelens array substrate 1211 and the amount of a warp of the lens arraysubstrate 1211 are further reduced as compared to Comparative StructureExamples 4 and 5.

Comparative Structure Example 7

However, practically, the shapes of the substrates with lenses that formthe stacked lens structure assembled into a camera module are not thesame. More specifically, among the plurality of substrates with lensesthat forms a stacked lens structure, for example, the thicknesses of thesubstrates with lenses and the sizes of the through-holes may bedifferent and the thicknesses, shapes, volumes, and the like of lensesformed in the through-holes may be different. Further specifically, thethickness of a photo-curable resin formed on the upper surface and thelower surface of a substrate with lenses may be different from onesubstrate with lenses to another.

FIG. 49 is a cross-sectional view of a stacked lens structure formed bystacking three substrates with lenses as a seventh substrate structure(hereinafter referred to as Comparative Structure Example 7). In thisstacked lens structure, similarly to Comparative Structure Example 6illustrated in FIGS. 48A to 48C, it is assumed that the layer and thearea of the photo-curable resin disposed on the upper surface and thelower surface of each of the substrates with lenses are the same.

A stacked lens structure 1311 illustrated in FIG. 49 includes threesubstrates with lenses 1321 to 1323.

In the following description, among the three substrates with lenses1321 to 1323, the substrate with lenses 1321 on the middle layer will bereferred to as a first substrate with lenses 1321, the substrate withlenses 1322 on the top layer will be referred to as a second substratewith lenses 1322, and the substrate with lenses 1323 on the bottom layerwill be referred to as a third substrate with lenses 1323.

The substrate thickness and the lens thickness in the second substratewith lenses 1322 disposed on the top layer are different from those ofthe third substrate with lenses 1323 disposed on the bottom layer.

More specifically, the lens thickness in the third substrate with lenses1323 is larger than the lens thickness in the second substrate withlenses 1322. Thus, the substrate thickness in the third substrate withlenses 1323 is larger than the substrate thickness in the secondsubstrate with lenses 1322.

A resin 1341 is formed on an entire contact surface between the firstand second substrates with lenses 1321 and 1322 and an entire contactsurface between the first and third substrates with lenses 1321 and1323.

The cross-sectional shape of the through-holes of the three substrateswith lenses 1321 to 1323 has such a so-called fan shape that the uppersurface of the substrate is wider than the lower surface of thesubstrate.

The effect of the three substrates with lenses 1321 to 1323 havingdifferent shapes will be described with reference to FIGS. 50A to 50D.

FIGS. 50A to 50C are diagrams schematically illustrating the stackedlens structure 1311 illustrated in FIG. 49.

As in this stacked lens structure 1311, when the second and thirdsubstrates with lenses 1322 and 1323 having different substratethicknesses are disposed on the upper surface and the lower surface ofthe first substrate with lenses 1321, respectively, the force of warpingthe stacked lens structure 1311 and the amount of a warp of the stackedlens structure 1311 change depending on the position in the thicknessdirection of the stacked lens structure 1311 at which the layer of theresin 1341 present in the entire contact surface of the three substrateswith lenses 1321 to 1323 is present.

Unless the layer of the resin 1341 present in the entire contact surfaceof the three substrates with lenses 1321 to 1323 is disposed symmetricalabout a line that passes through the central line (that is, the centralpoint in the thickness direction of the stacked lens structure 1311) ofthe stacked lens structure 1311 and runs in the plane direction of thesubstrate, the effect of the force occurring due to a curing shrinkageof the resin 1341 disposed on the upper surface and the lower surface ofthe first substrate with lenses 1321 is not canceled completely asillustrated in FIG. 48C. As a result, the stacked lens structure 1311warps in a certain direction.

For example, when the two layers of the resin 1341 on the upper surfaceand the lower surface of the first substrate with lenses 1321 aredisposed to be shifted in an upper direction than the central line inthe thickness direction of the stacked lens structure 1311, if a curingshrinkage occurs in the two layers of the resin 1341, the stacked lensstructure 1311 warps in a downward convex shape as illustrated in FIG.50C.

Further, when the cross-sectional shape of the through-hole in a thinnersubstrate among the second and third substrates with lenses 1322 and1323 has such a shape that widens toward the first substrate with lenses1321, the possibility of the loss or breakage of lenses may increase.

In the example illustrated in FIG. 49, the cross-sectional shape of thethrough-hole in the second substrate with lenses 1322 having the smallerthickness among the second and third substrates with lenses 1322 and1323 has such a fan shape that widens toward the first substrate withlenses 1321. In such a shape, when a curing shrinkage occurs in the twolayers of the resin 1341 on the upper surface and the lower surface ofthe first substrate with lenses 1321, force that warps the stacked lensstructure 1311 in a downward convex shape as illustrated in FIG. 50Cacts on the stacked lens structure 1311. This force acts as force actingin the direction of separating the lenses and the substrate in thesecond substrate with lenses 1322 as illustrated in FIG. 50D. With thisaction, the possibility that the lenses 1332 of the second substratewith lenses 1322 are lost or broken increases.

Next, a case in which a resin is expanded thermally will be considered.

Comparative Structure Example 8

FIG. 51 is a cross-sectional view of a stacked lens structure formed bystacking three substrates with lenses as an eighth substrate structure(hereinafter referred to as Comparative Structure Example 8). In thisstacked lens structure, similarly to Comparative Structure Example 6illustrated in FIGS. 48A to 48C, it is assumed that the layer and thearea of the photo-curable resin disposed on the upper surface and thelower surface of each of the substrates with lenses are the same.Comparative Structure Example 8 illustrated in FIG. 51 is different fromComparative Structure Example 7 illustrated in FIG. 49 in that thecross-sectional shape of the through-holes of the three substrates withlenses 1321 to 1323 has such a so-called downward tapered shape that thelower surface of the substrate is narrower than the upper surface of thesubstrate.

FIGS. 52A to 52C are diagrams schematically illustrating the stackedlens structure 1311 illustrated in FIG. 51.

When a user actually uses a camera module, the temperature in thehousing of a camera increases with an increase in power consumptionaccompanied by the operation of the camera and the temperature of thecamera module also increases. With this temperature rise, the resin 1341disposed on the upper surface and the lower surface of the firstsubstrate with lenses 1321 of the stacked lens structure 1311illustrated in FIG. 51 is expanded thermally.

Even when the area and the thickness of the resin 1341 disposed on theupper surface and the lower surface of the first substrate with lenses1321 are the same as illustrated in FIG. 48A, unless the layer of theresin 1341 present in the entire contact surface of the three substrateswith lenses 1321 to 1323 is disposed symmetrical about a line thatpasses through the central line (that is, the central point in thethickness direction of the stacked lens structure 1311) of the stackedlens structure 1311 and runs in the plane direction of the substrate,the effect of the force occurring due to thermal expansion of the resin1341 disposed on the upper surface and the lower surface of the firstsubstrate with lenses 1321 is not canceled completely as illustrated inFIG. 48C. As a result, the stacked lens structure 1311 warps in acertain direction.

For example, when the two layers of the resin 1341 on the upper surfaceand the lower surface of the first substrate with lenses 1321 aredisposed to be shifted in an upper direction than the central line inthe thickness direction of the stacked lens structure 1311, if thermalexpansion occurs in the two layers of the resin 1341, the stacked lensstructure 1311 warps in an upward convex shape as illustrated in FIG.52C.

Further, in the example illustrated in FIG. 51, the cross-sectionalshape of the through-hole of the second substrate with lenses 1322having a smaller thickness among the second and third substrates withlenses 1322 and 1323 has a downward tapered shape that narrows towardthe first substrate with lenses 1321. In such a shape, when the twolayers of the resin 1341 on the upper surface and the lower surface ofthe first substrate with lenses 1321 is thermally expanded, force thatwarps the stacked lens structure 1311 in an upward convex shape acts onthe stacked lens structure 1311. This force acts as force acting in thedirection of separating the lenses and the substrate in the secondsubstrate with lenses 1322 as illustrated in FIG. 52D. With this action,the possibility that the lenses 1332 of the second substrate with lenses1322 are lost or broken increases.

<Present Structure>

FIGS. 53A and 53B are diagrams illustrating a stacked lens structure1371 including three substrates with lenses 1361 to 1363, which employsthe present structure.

FIG. 53A illustrates a structure corresponding to the stacked lensstructure 1311 illustrated in FIG. 49, in which the cross-sectionalshape of the through-hole has a so-called fan shape. On the other hand,FIG. 53B illustrates a structure corresponding to the stacked lensstructure 1311 illustrated in FIG. 51, in which the cross-sectionalshape of the through-hole has a so-called downward tapered shape.

FIGS. 54A to 54C are diagrams schematically illustrating the stackedlens structure 1371 illustrated in FIGS. 53A and 53B in order todescribe the effect of the present structure.

The stacked lens structure 1371 has a structure in which a secondsubstrate with lenses 1362 is disposed on a first substrate with lenses1361 at the center, and a third substrate with lenses 1363 is disposedunder the first substrate with lenses 1361.

The substrate thickness and the lens thickness in the second substratewith lenses 1362 disposed on the top layer are different from those ofthe third substrate with lenses 1363 disposed on the bottom layer. Morespecifically, the lens thickness in the third substrate with lenses 1363is larger than the lens thickness in the second substrate with lenses1362. Thus, the substrate thickness in the third substrate with lenses1363 is larger than the substrate thickness in the second substrate withlenses 1362.

In the stacked lens structure 1371 of the present structure, directbonding of substrates is used as the means for fixing substrates withlenses. In other words, substrates with lenses to be fixed are subjectedto a plasma activation process, and two substrates with lenses to befixed are plasma-bonded. In still other words, a silicon oxide film isformed on the surfaces of the two substrates with lenses to be stacked,and a hydroxyl radical is combined with the film. After that, the twosubstrates with lenses are attached together and are heated andsubjected to dehydration condensation. In this way, the two substrateswith lenses are direct-bonded by a silicon-oxygen covalent bond.

Thus, in the stacked lens structure 1371 of the present structure,resin-based attachment is not used as the means for fixing substrateswith lenses. Due to this, a resin for forming lenses or a resin forattaching substrates is not disposed between the substrates with lenses.Moreover, since a resin is not disposed on the upper surface or thelower surface of the substrate with lenses, thermal expansion or acuring shrinkage of the resin does not occur in the upper surface or thelower surface of the substrate with lenses.

Thus, in the stacked lens structure 1371 even when the second and thirdsubstrates with lenses 1362 and 1363 having different lens thicknessesand different substrate thicknesses are disposed on the upper and lowersurfaces of the first substrates with lenses 1351, respectively, a warpof the substrate resulting from a curing shrinkage and a warp of thesubstrate resulting from thermal expansion do not occur unlikeComparative Structure Examples 1 to 8 described above.

That is, the present structure in which substrates with lenses are fixedby direct bonding provides an effect and an advantage that, even whensubstrates with lenses having different lens thicknesses and differentsubstrate thicknesses are stacked on and under the present structure, itis possible to suppress a warp of the substrate more effectively thanComparative Structure Examples 1 to 8 described above.

16. Various Modifications

Other modifications of the respective embodiments described above willbe described below.

<16.1 Cover Glass with Optical Diaphragms>

A cover glass is sometimes provided in an upper portion of the stackedlens structure 11 in order to protect the surface of the lens 21 of thestacked lens structure 11. In this case, the cover glass may have thefunction of an optical diaphragm. FIG. 55 is a diagram illustrating afirst configuration example in which a cover glass has the function ofan optical diaphragm.

In the first configuration example in which a cover glass has thefunction of an optical diaphragm as illustrated in FIG. 55, a coverglass 1501 is further stacked on the stacked lens structure 11.Moreover, a lens barrel 74 is disposed on an outer side of the stackedlens structure 11 and the cover glass 1501.

A light blocking film 1502 is formed on a surface (in the drawing, thelower surface of the cover glass 1501) of the cover glass 1501 close tothe substrate with lenses 41 a. Here, a predetermined range from thelens centers (optical centers) of the substrates with lenses 41 a to 41e is configured as an opening 1503 in which the light blocking film 1502is not formed, and the opening 1503 functions as an optical diaphragm.In this way, the diaphragm plate 51 formed in the camera module 1D orthe like illustrated in FIG. 13, for example, is omitted.

FIGS. 56A and 56B are diagrams for describing a method of manufacturingthe cover glass 1501 in which the light blocking film 1502 is formed.

First, as illustrated in FIG. 56A, a light absorbing material isdeposited by spin-coating to an entire area of one surface of the coverglass (glass substrate) 1501W in a wafer or panel form, for example,whereby the light blocking film 1502 is formed. As the light absorbingmaterial which forms the light blocking film 1502, a resin having lightabsorbing properties, containing a carbon black pigment or a titaniumblack pigment, for example, is used.

Subsequently, a predetermined region of the light blocking film 1502 isremoved by lithography or etching, whereby a plurality of openings 1503is formed at a predetermined interval as illustrated in FIG. 56B. Thearrangement of the openings 1503 corresponds to the arrangement of thethrough-holes 83 of the support substrate 81W illustrated in FIGS. 23Ato 23G in one-to-one correspondence. As another example of the method offorming the light blocking film 1502 and the opening 1503, a method ofjetting a light absorbing material that forms the light blocking film1502 to an area excluding the opening 1503 by an ink-jet method can beused.

After the cover glass 1501W in the substrate state manufactured in thisway is attached to a plurality of substrates with lenses 41W in thesubstrate state, the substrates with lenses 41W are divided by dicing orthe like which uses a blade or a laser. In this way, the stacked lensstructure 11 on which the cover glass 1501 having the diaphragm functionis stacked, illustrated in FIG. 55 is obtained.

When the cover glass 1501 is formed as a step of semiconductor processesin this manner, it is possible to suppress the occurrence of dust-causeddefects which may occur when the cover glass is formed by anotherassembling step.

According to the first configuration example illustrated in FIG. 55,since the optical diaphragm is formed by deposition, the light blockingfilm 1502 can be formed as thin as approximately 1 μm. Moreover, it ispossible to suppress deterioration (light attenuation in a peripheralportion) of an optical performance resulting from shielded incidentlight due to the diaphragm mechanism having a predetermined thickness.

In the above-described example, although the cover glass 1501W wasdivided after the cover glass 1501W was bonded to the plurality ofsubstrates with lenses 41W, the cover glass 1501W may be divided beforethe bonding. In other words, the bonding of the cover glass 1501 havingthe light blocking film 1502 and the five substrates with lenses 41 a to41 e may be performed in the wafer level or the chip level.

The surface of the light blocking film 1502 may be roughened. In thiscase, since it is possible to suppress surface reflection on the surfaceof the cover glass 1501 having the light blocking film 1502 formedthereon and to increase the surface area of the light blocking film1502, it is possible to improve the bonding strength between the coverglass 1501 and the substrate with lenses 41.

As an example of the method of roughening the surface of the lightblocking film 1502, a method of roughening the surface by etching or thelike after depositing a light absorbing material that forms the lightblocking film 1502, a method of depositing a light absorbing materialafter roughening the surface of the cover glass 1501 before depositionof the light absorbing material, a method of forming an uneven surfaceafter forming the film using a coagulating light absorbing material, anda method of forming an uneven surface after forming the film using alight absorbing material that contains a solid content may be used.

Moreover, an anti-reflection film may be formed between the lightblocking film 1502 and the cover glass 1501.

Since the cover glass 1501 also serves as the support substrate of thediaphragm, it is possible to reduce the size of the camera module 1.

FIG. 57 is a diagram illustrating a second configuration example inwhich a cover glass has the function of an optical diaphragm.

In the second configuration example in which the cover glass has thefunction of an optical diaphragm, as illustrated in FIG. 57, the coverglass 1501 is disposed at the position of the opening of the lens barrel74. The other configuration is the same as that of the firstconfiguration example illustrated in FIG. 55.

FIG. 58 is a diagram illustrating a third configuration example in whicha cover glass has the function of an optical diaphragm.

In the third configuration example in which the cover glass has thefunction of an optical diaphragm as illustrated in FIG. 58, the lightblocking film 1502 is formed on an upper surface of the cover glass 1501(that is, on the opposite side from the substrate with lenses 41 a). Theother configuration is the same as that of the first configurationexample illustrated in FIG. 55.

In the configuration in which the cover glass 1501 is disposed in theopening of the lens barrel 74 as illustrated in FIG. 57, the lightblocking film 1502 may be formed on the upper surface of the cover glass1501.

<16.2 Forming Diaphragm Using Through-Hole>

Next, an example in which the opening itself of the through-hole 83 ofthe substrate with lenses 41 is configured as a diaphragm mechanisminstead of the diaphragm which uses the diaphragm plate 51 or the coverglass 1501 will be described.

FIG. 59A is a diagram illustrating a first configuration example inwhich the opening itself of the through-hole 83 is configured as adiaphragm mechanism.

In description of FIGS. 59A to 59C, only different portions from thoseof the stacked lens structure 11 illustrated in FIG. 58 will bedescribed, and the description of the same portions will be omittedappropriately. Moreover, in FIGS. 59A to 59C, reference numeralsnecessary for description only are added in order to prevent thedrawings from becoming complex.

A stacked lens structure 11 f illustrated in FIG. 59A has aconfiguration in which the substrate with lenses 41 a located closest tothe light incidence side and farthest from the light receiving element12 among the five substrates with lenses 41 a to 41 e that form thestacked lens structure 11 illustrated in FIG. 58 is replaced with asubstrate with lenses 41 f.

When the substrate with lenses 41 f is compared with the substrate withlenses 41 a illustrated in FIG. 58, the hole diameter in the uppersurface of the substrate with lenses 41 a illustrated in FIG. 58 islarger than the hole diameter in the lower surface whereas the holediameter D1 in the upper surface of the substrate with lenses 41 fillustrated in FIGS. 59A to 59C is smaller than the hole diameter D2 inthe lower surface. That is, the cross-sectional shape of thethrough-hole 83 of the substrate with lenses 41 f has a so-called fanshape.

A height position of the top surface of the lens 21 formed in thethrough-hole 83 of the substrate with lenses 41 f is lower than theposition of the top surface of the substrate with lenses 41 f indicatedby a one-dot chain line in FIG. 59A.

In the stacked lens structure 11 f, the hole diameter on the lightincidence side of the through-hole 83 of the substrate with lenses 41 fon the top layer among the plurality of substrates with lenses 41 is thesmallest, whereby the portion (the portion corresponding to the holediameter D1) having the smallest hole diameter, of the through-hole 83functions as an optical diaphragm that limits the rays of incidentlight.

FIG. 59B is a diagram illustrating a second configuration example inwhich the opening itself of the through-hole 83 is configured as adiaphragm mechanism.

A stacked lens structure 11 g illustrated in FIG. 59B has aconfiguration in which the substrate with lenses 41 a on the top layeramong the five substrates with lenses 41 a to 41 e that form the stackedlens structure 11 illustrated in FIG. 58 is replaced with a substratewith lenses 41 g. Moreover, a substrate 1511 is further stacked on thesubstrate with lenses 41 g.

The hole diameter of the through-hole 83 of the substrate with lenses 41g has such a fan shape that the hole diameter on the light incidenceside is small similarly to the substrate with lenses 41 f illustrated inFIG. 59A. The substrate 1511 is a substrate that has the through-hole 83but does not hold the lens 21. The cross-sectional shapes of thethrough-holes 83 of the substrate with lenses 41 g and the substrate1511 have a so-called fan shape.

Since the substrate 1511 is stacked on the substrate with lenses 41 g, aplanar region on which incident light is incident is further narrowedthan the substrate with lenses 41 f illustrated in FIG. 59A. The holediameter D3 in the upper surface of the substrate 1511 is smaller thanthe hole diameter D4 in the curved surface portion (the lens portion 91)of the lens 21. Due to this, the portion (the portion corresponding tothe hole diameter D3) having the smallest hole diameter, of thethrough-hole 83 of the substrate 1511 functions as an optical diaphragmthat limits the rays of incident light.

When the position of the optical diaphragm is located as far as possiblefrom the lens 21 on the top surface of the stacked lens structure 11 g,it is possible to separate the exit pupil position from the opticaldiaphragm and to suppress shading.

As illustrated in FIG. 59B, when the substrate 1511 is further stackedon the five substrates with lenses 41 b to 41 e and 41 g, the positionof the optical diaphragm can be located as far as possible in theopposite direction from the light incidence direction from the lens 21of the substrate with lenses 41 g, which is the lens 21 on the topsurface of the stacked lens structure 11 g and the shading can besuppressed.

FIG. 59C is a diagram illustrating a third configuration example inwhich the opening itself of the through-hole 83 is configured as adiaphragm mechanism.

A stacked lens structure 11 h illustrated in FIG. 59C has aconfiguration in which a substrate 1512 is further stacked on thesubstrate with lenses 41 a among the five substrates with lenses 41 a to41 f that form the stacked lens structure 11 illustrated in FIG. 58.

The substrate 1512 is a substrate that has the through-hole 83 but doesnot hold the lens 21. The through-hole 83 of the substrate 1512 has sucha so-called fan shape that the hole diameter in the top surface of thesubstrate 1512 is different from that in the bottom surface, and thehole diameter D5 in the upper surface is smaller than the hole diameterD5 in the lower surface. Moreover, the hole diameter D5 in the topsurface of the substrate 1512 is smaller than the diameter of the curvedsurface portion (the lens portion 91) of the lens 21. Due to this, theportion (the portion corresponding to the hole diameter D5) having thesmallest hole diameter, of the through-hole 83 functions as an opticaldiaphragm that limits the rays of incident light. As another example ofthe shape of the substrate 1512, the substrate 1512 may have such aso-called downward tapered shape that the hole diameter D5 in the uppersurface is larger than the hole diameter D5 in the lower surface.

In the examples of FIGS. 59A to 59C, the hole diameter of thethrough-hole 83 of the substrate with lenses 41 f on the top surface (atthe position farthest from the light receiving element 12) among theplurality of substrates with lenses 41 that form the stacked lensstructure 11 is configured as the optical diaphragm or the hole diameterof the through-hole 83 of the substrate 1511 or 1512 disposed on the toplayer is configured as the optical diaphragm.

However, the hole diameter of any one of the through-holes 83 of thesubstrates with lenses 41 b to 41 e on layers other than the top layeramong the plurality of substrates with lenses 41 that form the stackedlens structure 11 may be configured similarly to the substrate withlenses 41 f or the substrate 1511 or 1512 so as to function as theoptical diaphragm.

However, from the perspective of suppressing the shading, as illustratedin FIGS. 59A to 59C, the substrate with lenses 41 having the function ofthe optical diaphragm may be disposed on the top layer or as close aspossible to the top layer (at the position farthest from the lightreceiving element 12).

As described above, when a predetermined one substrate with lenses 41among the plurality of substrates with lenses 41 that forms the stackedlens structure 11 or the substrate 1511 or 1512 that does not hold thelens 21 has the function of the optical diaphragm, it is possible toreduce the size of the stacked lens structure 11 and the camera module1.

When the optical diaphragm is integrated with the substrate with lenses41 that holds the lens 21, it is possible to improve the positionalaccuracy between the optical diaphragm and the curved lens surfaceclosest to the diaphragm which affects the imaging performance and toimprove the imaging performance.

<16.3 Wafer-Level Bonding Based on Metal Bonding>

In the above-described embodiment, although the substrates with lenses41W in which the lens 21 is formed in the through-hole 83 are attachedby plasma bonding, the substrates with lenses may be attached usingmetal bonding.

FIGS. 60A to 60E are diagrams for describing wafer-level attachmentusing metal bonding.

First, as illustrated in FIG. 60A, a substrate with lenses 1531W-a in asubstrate state in which a lens 1533 is formed in each of a plurality ofthrough-holes 1532 is prepared, and an anti-reflection film 1535 isformed on an upper surface and a lower surface of the substrate withlenses 1531W-a.

The substrate with lenses 1531W corresponds to the substrate with lenses41W in the substrate state described above. Moreover, theanti-reflection film 1535 corresponds to the upper surface layer 122 andthe lower surface layer 123 described above.

Here, a state in which a foreign material 1536 is mixed into a portionof the anti-reflection film 1535 formed on the upper surface of thesubstrate with lenses 1531W-a will be considered. The upper surface ofthe substrate with lenses 1531W-a is a surface that is bonded to asubstrate with lenses 1531W-b in the step of FIG. 60D.

Subsequently, as illustrated in FIG. 60B, a metal film 1542 is formed onthe upper surface of the substrate with lenses 1531W-a, which is thesurface bonded to the substrate with lenses 1531W-b. In this case, theportion of the through-hole 1532 in which the lens 1533 is formed ismasked using a metal mask 1541 so that the metal film 1542 is notformed.

Cu which is often used for metal bonding, for example, can be used as amaterial of the metal film 1542. As a method of forming the metal film1542, a PVD method such as a deposition method, a sputtering method, oran ion plating method which can form a film at a low temperature can beused.

Instead of Cu, Ni, Co, Mn, Al, Sn, In, Ag, Zn, or the like and an alloyof two or more of these materials may be used as the material of themetal film 1542. Moreover, materials other than the above-mentionedmaterials may be used as long as the materials are metal materials whichare easily plastically deformed.

As a method of forming the metal film 1542, an ink-jet method which usesmetal nanoparticals such as silver particles, for example, may be usedinstead of the method which uses a PVD method and a metal mask.

Subsequently, as illustrated in FIG. 60C, as a pre-treatment beforebonding, an oxide film formed on the surface of the metal film 1542 whenexposed to the air is removed using a reducible gas such as a formicacid, a hydrogen gas, or a hydrogen radical, whereby the surface of themetal film 1542 is cleaned.

As a method of cleaning the surface of the metal film 1542, Ar ions inthe plasma may be radiated to the metal surface to physically remove theoxide film by sputtering instead of using the reducible gas.

With the same steps as those illustrated in FIGS. 60A to 60C, asubstrate with lenses 1531W-b which is the other substrate with lenses1531W in the substrate state to be bonded is prepared.

Subsequently, as illustrated in FIG. 60D, the substrates with lenses1531W-a and 1531W-b are disposed so that the bonding surfaces thereofface each other and alignment is performed. After that, when appropriatepressure is applied, the metal film 1542 of the substrate with lenses1531W-a and the metal film 1542 of the substrate with lenses 1531W-b arebonded by metal bonding.

Here, it is assumed that a foreign material 1543 is also mixed into thelower surface of the substrate with lenses 1531W-b which is the bondingsurface of the substrate with lenses 1531W-b, for example. However, evenwhen the foreign materials 1536 and 1543 are present, since a metalmaterial which is easily plastically deformed is used as the metal film1542, the metal film 1542 is deformed and the substrates with lenses1531W-a and 1531W-b are bonded together.

Finally, as illustrated in FIG. 60E, a heat treatment is performed toaccelerate atomic bonding and crystallization of metal to increase thebonding strength. This heat treatment step may be omitted.

In this way, the substrates with lenses 1531W in which the lens 1533 isformed in each of the plurality of through-holes 1532 can be bondedusing metal bonding.

In order to realize bonding between the substrate with lenses 1531W-aand the metal film 1542, a film that serves as an adhesion layer may beformed between the substrate with lenses 1531W-a and the metal film1542. In this case, the adhesion layer is formed on an upper side (outerside) of the anti-reflection film 1535 (that is, between theanti-reflection film 1535 and the metal film 1542). Ti, Ta, W, or thelike, for example, can be used as the adhesion layer. Alternatively, anitride or an oxide of Ti, Ta, W, or the like or a stacked structure ofa nitride and an oxide may be used. The same can be applied to thebonding between the substrate with lenses 1531W-b and the metal film1542.

Moreover, the material of the metal film 1542 formed on the substratewith lenses 1531W-a and the material of the metal film 1542 formed onthe substrate with lenses 1531W-b may be different metal materials.

When the substrates with lenses 1531W in the substrate state are bondedby bonding metals which have a low Young's modulus and are easilyplastically deformed, even when a foreign material is present on abonding surface, the bonding surface is deformed by pressure and anecessary contact area is obtained.

When the plurality of substrates with lenses 1531W bonded using metalbonding is divided to obtain the stacked lens structure 11 and thestacked lens structure 11 is incorporated into the camera module 1,since the metal film 1542 has excellent sealing properties and canprevent light and moisture from entering the side surface, it ispossible to manufacture the stacked lens structure 11 and the cameramodule 1 which have high reliability.

<16.4 Substrate with Lenses Using Highly-Doped Substrate>

FIGS. 61A and 61B are cross-sectional views of substrates with lenses 41a′-1 and 41 a′-2 which are modifications of the substrate with lenses 41a described above.

In description of the substrates with lenses 41 a′-1 and 41 a′-2illustrated in FIGS. 61A and 61B, the description of the same portionsas those of the substrate with lenses 41 a described above will beomitted and the different portions only will be described.

The substrate with lenses 41 a′-1 illustrated in FIG. 61A is ahighly-doped substrate obtained by diffusing (ion-implanting) boron (B)of high concentration into a silicon substrate. An impurityconcentration in the substrate with lenses 41 a′-1 is approximately1×10¹⁹ cm⁻³, and the substrate with lenses 41 a′-1 can efficientlyabsorb light in a wide range of wavelengths.

The other configuration of the substrate with lenses 41 a′-1 is the sameas the substrate with lenses 41 a described above.

On the other hand, in the substrate with lenses 41 a′-2 illustrated inFIG. 61B, the region of the silicon substrate is divided into tworegions (that is, a first region 1551 and a second region 1552) havingdifferent impurity concentrations.

The first region 1551 is formed to a predetermined depth (for example,approximately 3 μm) from the substrate surface on the light incidenceside. The impurity concentration in the first region 1551 is as high asapproximately 1×10¹⁶ cm⁻³, for example. The impurity concentration inthe second region 1552 is approximately 1×10¹⁰ cm⁻³, for example, and islower than the first concentration. The ions diffused (ion-implanted)into the first and second regions 1551 and 1552 are boron (B) similarlyto the substrate with lenses 41 a′-1, for example.

The impurity concentration in the first region 1551 on the lightincidence side of the substrate with lenses 41 a′-2 is approximately1×10¹⁶ cm⁻³ and is lower than the impurity concentration (for example,1×10¹⁹ cm⁻³) of the substrate with lenses 41 a′-1. Thus, the thicknessof a light blocking film 121′ formed on a side wall of the through-hole83 of the substrate with lenses 41 a′-2 is larger than the thickness ofa light blocking film 121 of the substrate with lenses 41 a′-1illustrated in FIG. 61A.

For example, if the thickness of the light blocking film 121 of thesubstrate with lenses 41 a′-1 is 2 μm, the thickness of the lightblocking film 121′ of the substrate with lenses 41 a′-2 is 5 μm.

The other configuration of the substrate with lenses 41 a′-2 is the sameas the substrate with lenses 41 a described above.

As described above, when a highly-doped substrate is used as thesubstrates with lenses 41 a′-1 and 41 a′-2, since the substrate itselfcan absorb light which has passed through the light blocking film 121and the upper surface layer 122 and reached the substrate, it ispossible to suppress reflection of light. The doping amount can beappropriately set depending on the amount of light reaching thesubstrate and the thickness of the light blocking film 121 and the uppersurface layer 122 since it is only necessary to absorb light havingreached the substrate.

Moreover, since a silicon substrate which is easy to handle is used asthe substrates with lenses 41 a′-1 and 41 a′-2, it is easy to handle thesubstrates with lenses. Since the substrate itself can absorb lightwhich has passed through the light blocking film 121 and the uppersurface layer 122 and reached the substrate, it is possible to decreasethe thicknesses of the light blocking film 121, the upper surface layer122, and the stacked substrate itself and to simplify the structure.

In the substrates with lenses 41 a′-1 and 41 a′-2, the ion doped intothe silicon substrate is not limited to boron (B). Instead of this,phosphor (P), arsenic (As), antimony (Sb), or the like may be used, forexample. Further, an arbitrary element which can have a band structurethat increases the amount of absorbed light may be used.

The other substrates with lenses 41 b to 41 e that form the stacked lensstructure 11 may have the same configuration as the substrates withlenses 41 a′-1 and 41 a′-2.

<Manufacturing Method>

A method of manufacturing the substrate with lenses 41 a′-1 illustratedin FIG. 61A will be described with reference to FIGS. 62A to 62D.

First, as illustrated in FIG. 62A, a highly-doped substrate 1561W in asubstrate state in which boron (B) of a high concentration is diffused(ion-planted) is prepared. The impurity concentration of thehighly-doped substrate 1561W is approximately 1×10¹⁹ cm⁻³, for example.

Subsequently, as illustrated in FIG. 62B, through-holes 83 are formed byetching at predetermined positions of the highly-doped substrate 1561W.In FIGS. 62A to 62D, although only two through-holes 83 are illustrateddue to limitation of the drawing surface, a number of through-holes 83are actually formed in the plane direction of the highly-doped substrate1561W.

Subsequently, as illustrated in FIG. 62C, a light blocking film 121 isformed on a side wall of the through-hole 83 by depositing a blackresist material by spray coating.

Subsequently, as illustrated in FIG. 62D, a lens resin portion 82including the lens 21 is formed on the inner side of the through-hole 83by pressure molding using the upper mold 201 and the lower mold 181described with reference to FIGS. 23A to 23G.

After that, although not illustrated in the drawings, an upper surfacelayer 122 is formed on the upper surface of the highly-doped substrate1561W and the lens resin portion 82, and a lower surface layer 123 isformed on the lower surface of the highly-doped substrate 1561W and thelens resin portion 82, and the structure is divided. In this way, thesubstrate with lenses 41 a′-1 illustrated in FIG. 61A is obtained.

Next, a method of manufacturing the substrate with lenses 41 a′-2illustrated in FIG. 61B will be described with reference to FIGS. 63A to63F.

First, as illustrated in FIG. 63A, a doped substrate 1571W in asubstrate state in which boron (B) of a predetermined concentration isdiffused (ion-implanted) is prepared. The impurity concentration of thedoped substrate 1571W is approximately 1×10¹⁰ cm⁻³, for example.

Subsequently, as illustrated in FIG. 63B, through-holes 83 are formed byetching at predetermined positions of the doped substrate 1571W. InFIGS. 63A to 63F, although only two through-holes 83 are illustrated dueto limitation of the drawing surface, a number of through-holes 83 areactually formed in the plane direction of the doped substrate 1571W.

Subsequently, as illustrated in FIG. 63C, after boron (B) ision-implanted up to a predetermined depth (for example, approximately 3μm) from the substrate surface on the light incidence side of the dopedsubstrate 1571W, a heat treatment is performed at 900° C. As a result,as illustrated in FIG. 63D, a first region 1551 having a high impurityconcentration and a second region 1552 having a lower impurityconcentration are formed.

Subsequently, as illustrated in FIG. 63E, a light blocking film 121 isformed on a side wall of the through-hole 83 by depositing a blackresist material by spray coating.

Subsequently, as illustrated in FIG. 63F, a lens resin portion 82including the lens 21 is formed on the inner side of the through-hole 83by pressure molding using the upper mold 201 and the lower mold 181described with reference to FIGS. 23A to 23G.

After that, although not illustrated in the drawings, an upper surfacelayer 122 is formed on the upper surface of the doped substrate 1571Wand the lens resin portion 82, and a lower surface layer 123 is formedon the lower surface of the doped substrate 1571W and the lens resinportion 82, and the structure is divided. In this way, the substratewith lenses 41 a′-2 illustrated in FIG. 61B is obtained.

The respective substrates with lenses 41 a to 41 e that form the stackedlens structure 11 illustrated in FIGS. 1A and 1B may be configured assuch a highly-doped substrate as illustrated in FIGS. 61A and 61B. Inthis way, it is possible to increase the amount of light absorbed by thesubstrate itself.

17. Pixel Arrangement of Light Receiving Element and Structure and Useof Diaphragm Plate

Next, a pixel arrangement of the light receiving element 12 included inthe camera module 1 illustrated in FIGS. 10A to 10F. and FIGS. 11A to11D and the configuration of the diaphragm plate 51 will be describedfurther.

FIGS. 64A to 64D are diagrams illustrating examples of the planar shapeof the diaphragm plate 51 included in the camera module 1 illustrated inFIGS. 10A to 10F and FIGS. 11A to 11D.

The diaphragm plate 51 includes a shielding region 51 a that absorbs orreflects light to prevent entrance of the light and an opening region 51b that transmits light.

In the four optical units 13 included in the camera module 1 illustratedin FIGS. 10A to 10F and FIGS. 11A to 11D, the opening regions 51 b ofthe diaphragm plates 51 thereof may have the same opening diameter andmay have different opening diameters as illustrated in FIGS. 64A to 64D.In FIGS. 64A to 64D, symbols “L”, “M”, and “S” indicate that the openingdiameter of the opening region 51 b is “Large”, “Middle”, and “Small”,respectively.

In the diaphragm plate 51 illustrated in FIG. 64A, the four openingregions 51 b have the same opening diameter.

In the diaphragm plate 51 illustrated in FIG. 64B, two opening regions51 b are standard diaphragm openings having a “Middle” opening diameter.For example, as illustrated in FIG. 13, the diaphragm plate 51 mayslightly overlap the lens 21 of the substrate with lenses 41. That is,the opening region 51 b of the diaphragm plate 51 may be slightlysmaller than the diameter of the lens 21. The remaining two openingregions 51 b of the diaphragm plate 51 illustrated in FIG. 64B have a“Large” opening diameter. That is, the remaining two opening regions 51b have a larger opening diameter than the “Middle” opening diameter.These large opening regions 51 b have an effect of allowing a largeramount of light to enter the light receiving element 12 included in thecamera module 1 when the illuminance of a subject is low, for example.

In the diaphragm plate 51 illustrated in FIG. 64C, two opening regions51 b are standard diaphragm openings having a “Middle” opening diameter.The remaining two opening regions 51 b of the diaphragm plate 51illustrated in FIG. 64C have a “Small” opening diameter. That is, theremaining two opening regions 51 b have a smaller opening diameter thanthe “Middle” opening diameter. These small opening regions 51 b have aneffect of decreasing the amount of light entering the light receivingelement 12 when the illuminance of a subject is high, and the amount ofcharge generated in a photoelectric conversion unit included in thelight receiving element 12 may exceed a saturation charge amount of thephotoelectric conversion unit if light entering from these openingregions is incident on the light receiving element 12 included in thecamera module 1 through the opening regions 51 b having the “Middle”opening diameter, for example.

In the diaphragm plate 51 illustrated in FIG. 64D, two opening regions51 b are standard diaphragm openings having a “Middle” opening diameter.One of the remaining two opening regions 51 b of the diaphragm plate 51illustrated in FIG. 64D has the “Large” opening diameter and the otherhas the “Small” opening diameter. These opening regions 51 b have thesame effect as the opening regions 51 b having the “Large” and “Small”opening diameters described with reference to FIGS. 64B and 64C.

FIG. 65 illustrates a configuration of a light receiving area of thecamera module 1 illustrated in FIGS. 10A to 10F. and FIGS. 11A to 11D.

As illustrated in FIG. 65, the camera module 1 includes four opticalunits 13 (not illustrated). Moreover, light components incident on thesefour optical units 13 are received by light receiving unitscorresponding to the respective optical units 13. Thus, the lightreceiving element 12 of the camera module 1 illustrated in FIGS. 10A to10F. and FIGS. 11A to 11D includes four light receiving areas 1601 a 1to 1601 a 4.

As another embodiment related to the light receiving unit, the lightreceiving element 12 may include one light receiving area 1601 a thatreceives light incident on one optical unit 13 included in the cameramodule 1, and the camera module 1 includes a number of light receivingelements 12 corresponding to the number of optical units 13 included inthe camera module 1. For example, in the case of the camera module 1illustrated in FIGS. 10A to 10F. and FIGS. 11A to 11D, the camera module1 includes four optical units 13.

The light receiving areas 1601 a 1 to 1601 a 4 include pixel arrays 1601b 1 to 1601 b 4, respectively, in which pixels for receiving light arearranged in an array form.

In FIG. 65, for the sake of simplicity, a circuit for driving the pixelsincluded in the pixel array and a circuit for reading pixels are notillustrated, and the light receiving areas 1601 a 1 to 1601 a 4 areillustrated in the same size as the pixel arrays 1601 b 1 to 1601 b 4.

The pixel arrays 1601 b 1 to 1601 b 4 included in the light receivingareas 1601 a 1 to 1601 a 4 include pixel repetition units 1602 c 1 to1602 c 4 made up of a plurality of pixels. These repetition units 1602 c1 to 1602 c 4 are arranged in a plurality of array forms in bothvertical and horizontal directions whereby the pixel arrays 1601 b 1 to1601 b 4 are formed.

The optical units 13 are disposed on the four light receiving areas 1601a 1 to 1601 a 4 included in the light receiving element 12. The fouroptical units 13 include the diaphragm plate 51 as a part thereof. InFIG. 65, the opening region 51 b of the diaphragm plate 51 illustratedin FIG. 64D is depicted by a broken line as an example of the openingdiameter of the four opening regions 51 b of the diaphragm plate 51.

In the field of image signal processing, a super-resolution technique isknown as a technique of obtaining images having a high resolution byapplying the super-resolution technique to an original image. An examplethereof is disclosed in JP 2015-102794 A, for example.

The camera module 1 illustrated in FIGS. 10A to 10F and FIGS. 11A to 11Dmay have the structures illustrated in FIGS. 13, 16, 17, 34, 35, 37, and55 as a cross-sectional structure thereof.

In these camera modules 1, the optical axes of the two optical units 13each disposed in each of the vertical and horizontal directions of thesurface of the module 1 serving as the light incidence surface extend inthe same direction. Due to this, it is possible to obtain a plurality ofnon-identical images using different light receiving areas with theoptical axes extending in the same direction.

The camera module 1 having such a structure is suitable for obtaining animage having a higher resolution based on the obtained plurality oforiginal images than that of one image obtained from one optical unit 13by applying the super-resolution technique to these images.

FIGS. 66 to 69 illustrate configuration examples of pixels in the lightreceiving area of the camera module 1 illustrated in FIGS. 10A to 10Fand FIGS. 11A to 11D.

In FIGS. 66 to 69, G pixels indicate pixels that receive light in thegreen wavelength, R pixels indicate pixels that receive light in the redwavelength, and B pixels indicate pixels that receive light in the bluewavelength. C pixels indicate pixels that receive light in the entirewavelength region of visible light.

FIG. 66 illustrates a first example of a pixel arrangement of the fourpixel arrays 1601 b 1 to 1601 b 4 included in the light receivingelement 12 of the camera module 1.

The repetition units 1602 c 1 to 1602 c 4 are repeatedly arranged in rowand column directions in the four pixel arrays 1601 b 1 to 1601 b 4,respectively. The repetition units 1602 c 1 to 1602 c 4 illustrated inFIG. 66 are made up of R, G, B, and G pixels, respectively.

The pixel arrangement illustrated in FIG. 66 has an effect that thepixel arrangement is suitable for splitting incident light from asubject irradiated with visible light into red (R), green (G), and blue(B) light components to obtain an image made up of the three colors R,G, and B.

FIG. 67 illustrates a second example of a pixel arrangement of the fourpixel arrays 1601 b 1 to 1601 b 4 included in the light receivingelement 12 of the camera module 1.

In the pixel arrangement illustrated in FIG. 67, the combination ofwavelengths (colors) of light that the respective pixels that form therepetition units 1602 c 1 to 1602 c 4 receive is different from that ofthe pixel arrangement illustrated in FIG. 66. The repetition units 1602c 1 to 1602 c 4 illustrated in FIG. 67 are made up of R, G, B, and Cpixels, respectively.

The pixel arrangement illustrated in FIG. 67 does not split light intothe R, G, and B light components as described above but has C pixelsthat receive light in the entire wavelength region of visible light. TheC pixels receive a larger amount of light than the R, G, and B pixelsthat receive a portion of the split light components. Due to this, thisconfiguration has an effect that, even when the illuminance of a subjectis low, for example, it is possible to obtain an image having higherlightness or an image having a larger luminance gradation usinginformation (for example, luminance information of the subject) obtainedby the C pixels which receives a large amount of light.

FIG. 68 illustrates a third example of a pixel arrangement of the fourpixel arrays 1601 b 1 to 1601 b 4 included in the light receivingelement 12 of the camera module 1.

The repetition units 1602 c 1 to 1602 c 4 illustrated in FIG. 68 aremade up of R, C, B, and C pixels, respectively.

The pixel repetition units 1602 c 1 to 1602 c 4 illustrated in FIG. 68do not include G pixels. Information corresponding to the G pixels isobtained by arithmetically processing the information obtained from theC, R, and B pixels. For example, the information corresponding to the Gpixels is obtained by subtracting the output values of the R and Bpixels from the output value of the C pixels.

Each of the pixel repetition units 1602 c 1 to 1602 c 4 illustrated inFIG. 68 includes two C pixels that receive light in the entirewavelength region, which is twice the number of C pixels in each of therepetition units 1602 c 1 to 1602 c 4 illustrated in FIG. 67. Moreover,in the pixel repetition units 1602 c 1 to 1602 c 4 illustrated in FIG.68, two C pixels are disposed in the diagonal direction of the contourof the repetition unit 1602 c so that the pitch of C pixels in the pixelarray 1601 b illustrated in FIG. 68 is twice the pitch of C pixels inthe pixel array 1601 b illustrated in FIG. 67 in both vertical andhorizontal directions of the pixel array 1601 b.

Due to this, the configuration illustrated in FIG. 68 has an effectthat, even when the illuminance of a subject is low, for example, it ispossible to obtain information (for example, luminance information)obtained from the C pixels that receive a large amount of light with aresolution twice that of the configuration illustrated in FIG. 67whereby a clear image having a resolution twice higher than thatobtained by the configuration illustrated in FIG. 67 can be obtained.

FIG. 69 illustrates a fourth example of a pixel arrangement of the fourpixel arrays 1601 b 1 to 1601 b 4 included in the light receivingelement 12 of the camera module 1.

The repetition units 1602 c 1 to 1602 c 4 illustrated in FIG. 69 aremade up of R, C, C, and C pixels, respectively.

For example, when a camera module is used for a camera which is mountedon a vehicle to photograph the forward side of the vehicle, a colorimage is not typically necessary in many cases. It is often necessary torecognize a red brake lamp of a vehicle traveling on the forward sideand the red signal of a traffic signal on a road and to recognize theshape of other subjects.

Since the configuration illustrated in FIG. 69 includes R pixels whichcan recognize the red brake lamp of a vehicle and the red signal of atraffic signal on a road and includes a larger number of C pixels thatreceive a large amount of light than the C pixels included in the pixelrepetition unit 1602 c illustrated in FIG. 68, the configurationillustrated in FIG. 69 provides an effect that, even when theilluminance of a subject is low, for example, it is possible to obtain aclear image having a higher resolution.

The camera modules 1 including the light receiving element 12illustrated in FIGS. 66 to 69 may use any one of the shapes of thediaphragm plate 51 illustrated in FIGS. 64A to 64D.

In the camera module 1 illustrated in FIGS. 10A to 10F and FIGS. 11A to11D, including any one of the light receiving elements 12 illustrated inFIGS. 66 to 69 and the diaphragm plate 51 illustrated in any one ofFIGS. 64A to 64D, the optical axes of the two optical units 13 eachdisposed in the vertical and horizontal directions of the surface of thecamera module 1 serving as a light incidence surface extend in the samedirection.

The camera module 1 having such a structure has an effect that it ispossible to obtain an image having a higher resolution by applying thesuper-resolution technique to the obtained plurality of original images.

FIG. 70 illustrates a modification of the pixel arrangement illustratedin FIG. 66.

The repetition units 1602 c 1 to 1602 c 4 illustrated in FIG. 66 aremade up of R, G, B, and G pixels, respectively, and the two G pixels ofthe same color have the same structure. In contrast, the repetitionunits 1602 c 1 to 1602 c 4 illustrated in FIG. 70 are made up of R, G1,B, and G2 pixels, respectively, and the two G pixels of the same color(that is, G1 and G2 pixels) have different structures.

A signal generation unit (for example, a photodiode) included in the G2pixel has a higher appropriate operation limit (for example, asaturation charge amount) than the G1 pixel. Moreover, a signalconversion unit (for example, a charge voltage conversion capacitor)included in the G2 pixel is a larger size than the G1 pixel.

According to such a configuration, since an output signal of the G2pixel when the pixel generates a predetermined amount of signal (forexample, charge) per unit time is smaller than that of the G1 pixel andthe saturation charge amount of the G2 pixel is larger than that of theG1 pixel, the configuration provides an effect that, even when theilluminance of a subject is high, for example, the pixels do not reachits operation limit and an image having a high gradation is obtained.

On the other hand, since the G1 pixel when the pixel generates apredetermined amount of signal (for example, charge) per unit timeprovides a larger output signal than the G2 pixel, the configurationprovides an effect that, even when the illuminance of a subject is low,for example, an image having a high gradation is obtained.

Since the light receiving element 12 illustrated in FIG. 70 includessuch G1 and G2 pixels, the light receiving element 12 provides an effectthat an image having a high gradation in a wide illuminance range (thatis, an image having a wide dynamic range) is obtained.

FIG. 71 illustrates a modification of the pixel arrangement illustratedin FIG. 68.

The repetition units 1602 c 1 to 1602 c 4 illustrated in FIG. 68 aremade up of R, C, B, and C pixels, respectively, and the two C pixels ofthe same color have the same structure. In contrast, the repetitionunits 1602 c 1 to 1602 c 4 illustrated in FIG. 71 are made up of R, C1,B, and C2 pixels, respectively, and the two C pixels of the same color(that is, C1 and C2 pixels) have different structures.

A signal generation unit (for example, a photodiode) included in the C2pixel has a higher operation limit (for example, a saturation chargeamount) than the C1 pixel. Moreover, a signal conversion unit (forexample, a charge voltage conversion capacitor) included in the C2 pixelis a larger size than the C1 pixel.

FIG. 72 illustrates a modification of the pixel arrangement illustratedin FIG. 69.

The repetition units 1602 c 1 to 1602 c 4 illustrated in FIG. 69 aremade up of R, C, C, and C pixels, respectively, and the three C pixelsof the same color have the same structure. In contrast, the repetitionunits 1602 c 1 to 1602 c 4 illustrated in FIG. 72 are made up of R, C1,C2, and C3 pixels, respectively, and the three C pixels of the samecolor (that is, C1 to C3 pixels) have different structures.

For example, a signal generation unit (for example, a photodiode)included in the C2 pixel has a higher operation limit (for example, asaturation charge amount) than the C1 pixel, and a signal generationunit (for example, a photodiode) included in the C3 pixel has a higheroperation limit (for example, a saturation charge amount) than the C2pixel. Moreover, a signal conversion unit (for example, a charge voltageconversion capacitor) included in the C2 pixel is a larger size than theC1 pixel, and a signal conversion unit (for example, a charge voltageconversion capacitor) included in the C3 pixel is a larger size than theC2 pixel.

Since the light receiving element 12 illustrated in FIGS. 71 and 72 hasthe above-described configuration, the light receiving element 12provides an effect that an image having a high gradation in a wideilluminance range (that is, an image having a wide dynamic range) isobtained similarly to the light receiving element 12 illustrated in FIG.70.

The diaphragm plate 51 of the camera module 1 including the lightreceiving element 12 illustrated in FIGS. 70 to 72 may have variousconfigurations of the diaphragm plates 51 illustrated in FIGS. 64A to64D and the modifications thereof.

In the camera module 1 illustrated in FIGS. 10A to 10F and FIGS. 11A to11D, including any one of the light receiving elements 12 illustrated inFIGS. 70 to 72 and the diaphragm plate 51 illustrated in any one ofFIGS. 64A to 64D, the optical axes of the two optical units 13 eachdisposed in the vertical and horizontal directions of the surface of thecamera module 1 serving as a light incidence surface extend in the samedirection.

The camera module 1 having such a structure has an effect that it ispossible to obtain an image having a higher resolution by applying thesuper-resolution technique to the obtained plurality of original images.

FIG. 73A illustrates a fifth example of the pixel arrangement of thefour pixel arrays 1601 b 1 to 1601 b 4 included in the light receivingelement 12 of the camera module 1.

The four pixel arrays 1601 b 1 to 1601 b 4 included in the lightreceiving element 12 may not necessarily have the same structure asdescribed above but may have different structures as illustrated in FIG.73A.

In the light receiving element 12 illustrated in FIG. 73A, the pixelarrays 1601 b 1 and 1601 b 4 have the same structure and the repetitionunits 1602 c 1 and 1602 c 4 that form the pixel arrays 1601 b 1 and 1601b 4 have the same structure.

In contrast, the pixel arrays 1601 b 2 and 1601 b 3 have a differentstructure from the pixel arrays 1601 b 1 and 1601 b 4. Specifically, thepixels included in the repetition units 1602 c 2 and 1602 c 3 of thepixel arrays 1601 b 2 and 1601 b 3 have a larger size than the pixels ofthe repetition units 1602 c 1 and 1602 c 4 of the pixel arrays 1601 b 1and 1601 b 4. More specifically, the photoelectric conversion unitincluded in the pixels of the repetition units 1602 c 2 and 1602 c 3 hasa larger size than that of the repetition units 1602 c 1 and 1602 c 4.The region of the repetition units 1602 c 2 and 1602 c 3 has a largersize than the region of the repetition units 1602 c 1 and 1602 c 4 sincethe pixels of the repetition units 1602 c 2 and 1602 c 3 have a largersize than the pixels of the repetition units 1602 c 1 and 1602 c 4. Dueto this, although the pixel arrays 1601 b 2 and 1601 b 3 have the samearea as the pixel arrays 1601 b 1 and 1601 b 4, the pixel arrays 1601 b2 and 1601 b 3 are made up of a smaller number of pixels than the pixelarrays 1601 b 1 and 1601 b 4.

The diaphragm plate 51 of the camera module 1 including the lightreceiving element 12 illustrated in FIG. 73A may have variousconfigurations of the diaphragm plates 51 illustrated in FIGS. 64A to64C, the configurations of the diaphragm plates 51 illustrated in FIGS.73B to 73D, or the modifications thereof.

In general, a light receiving element which uses large pixels providesan effect that an image having a better signal-to-noise ratio (S/Nratio) than a light receiving element which uses small pixels isobtained.

Although the magnitude of noise generated in a signal readout circuitand a signal amplification circuit in a light receiving element whichuses large pixels is the same as that of a light receiving element whichuses small pixels, the magnitude of a signal generated by a signalgeneration unit included in a pixel increases as the size of a pixelincreases.

Due to this, the light receiving element which uses large pixelsprovides an effect that an image having a better signal-to-noise ratio(S/N ratio) than the light receiving element which uses small pixels isobtained.

On the other hand, if the size of a pixel array is the same, a lightreceiving element which uses small pixels provides a higher resolutionthan a light receiving element which uses large pixels.

Due to this, the light receiving element which uses small pixelsprovides an effect that an image having a higher resolution than thelight receiving element which uses large pixels is obtained.

The configuration of the light receiving element 12 illustrated in FIG.73A provides an effect that, when the illuminance of a subject is high,and therefore, a large signal is obtained in the light receiving element12, for example, it is possible to obtain images having a highresolution using the light receiving areas 1601 a 1 and 1601 a 4 inwhich the pixels have a small size and the resolution is high, and animage having a high resolution is obtained by applying thesuper-resolution technique to these two images.

Moreover, it is possible to provide an effect that, when the illuminanceof a subject is low, and therefore, there is a possibility that the S/Nratio of an image decreases because a large signal is not obtained inthe light receiving element 12, for example, it is possible to obtainimages having a high S/N ratio using the light receiving areas 1601 a 2and 1601 a 3 in which images having a high S/N ratio are obtained, andan image having a high resolution is obtained by applying thesuper-resolution technique to these two images.

In this case, as the shape of the diaphragm plate 51, the camera module1 including the light receiving element 12 illustrated in FIG. 73A mayuse the shape of the diaphragm plate 51 illustrated in FIG. 73B, forexample, among the three shapes of the diaphragm plates 51 illustratedin FIGS. 73B to 73D.

In the diaphragm plate 51 illustrated in FIG. 73C, for example, amongthe three shapes of the diaphragm plates 51 illustrated in FIGS. 73B to73D, the opening region 51 b of the diaphragm plate 51 which is used incombination with the light receiving areas 1601 a 2 and 1601 a 3 whichuse large pixels is larger than the opening region 51 b of the diaphragmplate 51 which is used in combination with the other light receivingarea.

Due to this, the camera module 1 which uses a combination of the lightreceiving element 12 illustrated in FIG. 73A and the diaphragm plate 51illustrated in FIG. 73C among the three shapes of the diaphragm plates51 illustrated in FIGS. 73B to 73D provides an effect that, when theilluminance of a subject is low, and therefore, a large signal is notobtained in the light receiving element 12, for example, images having ahigher S/N ratio can be obtained in the light receiving areas 1601 a 2and 1601 a 3 than the camera module 1 which uses a combination of thelight receiving element 12 illustrated in FIG. 73A and the diaphragmplate 51 illustrated in FIG. 73B.

In the diaphragm plate 51 illustrated in FIG. 73D, for example, amongthe three shapes of the diaphragm plates 51 illustrated in FIGS. 73B to73D, the opening region 51 b of the diaphragm plate 51 which is used incombination with the light receiving areas 1601 a 2 and 1601 a 3 whichuse large pixels is smaller than the opening region 51 b of thediaphragm plate 51 which is used in combination with the other lightreceiving area.

Due to this, the camera module 1 which uses a combination of the lightreceiving element 12 illustrated in FIG. 73A and the diaphragm plate 51illustrated in FIG. 73D among the three shapes of the diaphragm plates51 illustrated in FIGS. 73B to 73D provides an effect that, when theilluminance of a subject is high, and therefore, a large signal is notobtained in the light receiving element 12, for example, the amount oflight incident on the light receiving areas 1601 a 2 and 1601 a 3 issuppressed more than the camera module 1 which uses a combination of thelight receiving element 12 illustrated in FIG. 73A and the diaphragmplate 51 illustrated in FIG. 73B among the three shapes of the diaphragmplates 51 illustrated in FIGS. 73B to 73D.

Due to this, it is possible to provide an effect of suppressing theoccurrence of a situation in which an excessively large amount of lightenters the pixels included in the light receiving areas 1601 a 2 and1601 a 3, and as a result, an appropriate operation limit (for example,the saturation charge amount) of the pixels included in the lightreceiving areas 1601 a 2 and 1601 a 3 is exceeded.

FIG. 74A illustrates a sixth example of the pixel arrangement of thefour pixel arrays 1601 b 1 to 1601 b 4 included in the light receivingelement 12 of the camera module 1.

In the light receiving element 12 illustrated in FIG. 74A, the region ofthe repetition unit 1602 c 1 of the pixel array 1601 b 1 has a smallersize than the region of the repetition units 1602 c 1 and 1602 c 2 ofthe pixel arrays 1601 b 2 and 1601 b 3. The region of the repetitionunit 1602 c 4 of the pixel array 1601 b 4 has a larger size than theregion of the repetition units 1602 c 1 and 1602 c 2 of the pixel arrays1601 b 2 and 1601 b 3.

That is, the sizes of the regions of the repetition units 1602 c 1 to1602 c 4 have such a relation that (Repetition unit 1602 c1)<[(Repetition unit 1602 c 2)=(Repetition unit 1602 c 3)]<(Repetitionunit 1602 c 4).

The larger the size of the region of each of the repetition units 1602 c1 to 1602 c 4, the larger becomes the pixel size and the larger becomesthe size of the photoelectric conversion unit.

The diaphragm plate 51 of the camera module 1 including the lightreceiving element 12 illustrated in FIG. 74A may have variousconfigurations of the diaphragm plates 51 illustrated in FIGS. 64A to64C, the configurations of the diaphragm plates 51 illustrated in FIGS.74B to 74D, or the modifications thereof.

The configuration of the light receiving element 12 illustrated in FIG.74A provides an effect that, when the illuminance of a subject is high,and therefore, a large signal is obtained in the light receiving element12, for example, it is possible to obtain images having a highresolution using the light receiving area 1601 a 1 in which the pixelshave a small size and the resolution is high.

Moreover, it is possible to provide an effect that, when the illuminanceof a subject is low, and therefore, there is a possibility that the S/Nratio of an image decreases because a large signal is not obtained inthe light receiving element 12, for example, it is possible to obtainimages having a high S/N ratio using the light receiving areas 1601 a 2and 1601 a 3 in which images having a high S/N ratio are obtained, andan image having a high resolution is obtained by applying thesuper-resolution technique to these two images.

Further, it is possible to provide an effect that, when the illuminanceof a subject is further lower, and therefore, there is a possibilitythat the S/N ratio of an image decreases further in the light receivingelement 12, for example, it is possible to obtain images having a higherS/N ratio using the light receiving area 1601 a 4 in which images havinga higher S/N ratio are obtained.

In this case, as the shape of the diaphragm plate 51, the camera module1 including the light receiving element 12 illustrated in FIG. 74A mayuse the shape of the diaphragm plate 51 illustrated in FIG. 74B, forexample, among the three shapes of the diaphragm plates 51 illustratedin FIGS. 74B to 74D.

In the diaphragm plate 51 illustrated in FIG. 74C, for example, amongthe three shapes of the diaphragm plates 51 illustrated in FIGS. 74B to74D, the opening region 51 b of the diaphragm plate 51 which is used incombination with the light receiving areas 1601 a 2 and 1601 a 3 whichuse large pixels is larger than the opening region 51 b of the diaphragmplate 51 which is used in combination with the light receiving area 1601a 1 which use small pixels. Moreover, the opening region 51 b of thediaphragm plate 51 which is used in combination with the light receivingarea 1601 a 4 which use still larger pixels is still larger.

Due to this, the camera module 1 which uses a combination of the lightreceiving element 12 illustrated in FIG. 74A and the diaphragm plate 51illustrated in FIG. 74C among the three shapes of the diaphragm plates51 illustrated in FIGS. 74B to 74D provides an effect that, when theilluminance of a subject is low, and therefore, a large signal is notobtained in the light receiving element 12, for example, images having ahigher S/N ratio can be obtained in the light receiving areas 1601 a 2and 1601 a 3 and that, when the illuminance of a subject is furtherlower, for example, it is possible to obtain images having a higher S/Nratio in the light receiving area 1601 a 4 than the camera module 1which uses a combination of the light receiving element 12 illustratedin FIG. 74A and the diaphragm plate 51 illustrated in FIG. 74B among thethree shapes of the diaphragm plates 51 illustrated in FIGS. 74B to 74D.

In the diaphragm plate 51 illustrated in FIG. 74D, for example, amongthe three shapes of the diaphragm plates 51 illustrated in FIGS. 74B to74D, the opening region 51 b of the diaphragm plate 51 which is used incombination with the light receiving areas 1601 a 2 and 1601 a 3 whichuse large pixels is smaller than the opening region 51 b of thediaphragm plate 51 which is used in combination with the light receivingarea 1601 a 1 which use small pixels. Moreover, the opening region 51 bof the diaphragm plate 51 which is used in combination with the lightreceiving area 1601 a 4 which use still larger pixels is still smaller.

Due to this, the camera module 1 which uses a combination of the lightreceiving element 12 illustrated in FIG. 74A and the diaphragm plate 51illustrated in FIG. 74D among the three shapes of the diaphragm plates51 illustrated in FIGS. 74B to 74D provides an effect that, when theilluminance of a subject is high, and therefore, a large signal isobtained in the light receiving element 12, for example, the amount oflight incident on the light receiving areas 1601 a 2 and 1601 a 3 issuppressed more than the camera module 1 which uses a combination of thelight receiving element 12 illustrated in FIG. 74A and the diaphragmplate 51 illustrated in FIG. 74B among the three shapes of the diaphragmplates 51 illustrated in FIGS. 74B to 74D.

Due to this, it is possible to provide an effect of suppressing theoccurrence of a situation in which an excessively large amount of lightenters the pixels included in the light receiving areas 1601 a 2 and1601 a 3, and as a result, an appropriate operation limit (for example,the saturation charge amount) of the pixels included in the lightreceiving area 1601 a 2 and 1601 a 3 is exceeded.

Moreover, it is possible to provide an effect of further suppressing theamount of light incident on the light receiving area 1601 a 4 to therebysuppress the occurrence of a situation in which an excessively largeamount of light enters the pixels included in the light receiving area1601 a 4, and as a result, an appropriate operation limit (for example,the saturation charge amount) of the pixels included in the lightreceiving area 1601 a 4 is exceeded.

As another embodiment, using a structure similar to a diaphragm thatchanges the size of an opening by combining a plurality of plates andchanging a positional relation thereof as is used in a general camera,for example, a structure may be used in which a camera module includesthe diaphragm plate 51 of which the opening region 51 b is variable andthe size of the opening of a diaphragm is changed according to theilluminance of a subject.

For example, when the light receiving element 12 illustrated in FIG. 73Aor 74A is used, a structure may be used in which the shape illustratedin FIG. 73C or 74C among the three shapes of the diaphragm plates 51illustrated in FIGS. 73B to 73D or FIGS. 74B to 74D is used when theilluminance of a subject is low, the shape illustrated in FIG. 73B or74B is used when the illuminance of the subject is higher than theabove-mentioned illuminance, and the shape illustrated in FIG. 73D or74D is used when the illuminance of the subject is further higher thanthe above-mentioned illuminance.

FIG. 75 illustrates a seventh example of the pixel arrangement of thefour pixel arrays 1601 b 1 to 1601 b 4 included in the light receivingelement 12 of the camera module 1.

In the light receiving element 12 illustrated in FIG. 75, all pixels ofthe pixel array 1601 b 1 are made up of pixels that receive light in thegreen wavelength. All pixels of the pixel array 1601 b 2 are made up ofpixels that receive light in the blue wavelength. All pixels of thepixel array 1601 b 3 are made up of pixels that receive light in the redwavelength. All pixels of the pixel array 1601 b 4 are made up of pixelsthat receive light in the green wavelength.

FIG. 76 illustrates an eighth example of the pixel arrangement of thefour pixel arrays 1601 b 1 to 1601 b 4 included in the light receivingelement 12 of the camera module 1.

In the light receiving element 12 illustrated in FIG. 76, all pixels ofthe pixel array 1601 b 1 are made up of pixels that receive light in thegreen wavelength. All pixels of the pixel array 1601 b 2 are made up ofpixels that receive light in the blue wavelength. All pixels of thepixel array 1601 b 3 are made up of pixels that receive light in the redwavelength. All pixels of the pixel array 1601 b 4 are made up of pixelsthat receive light in the entire wavelength region of visible light.

FIG. 77 illustrates a ninth example of the pixel arrangement of the fourpixel arrays 1601 b 1 to 1601 b 4 included in the light receivingelement 12 of the camera module 1.

In the light receiving element 12 illustrated in FIG. 77, all pixels ofthe pixel array 1601 b 1 are made up of pixels that receive light in theentire wavelength region of visible light. All pixels of the pixel array1601 b 2 are made up of pixels that receive light in the bluewavelength. All pixels of the pixel array 1601 b 3 are made up of pixelsthat receive light in the red wavelength. All pixels of the pixel array1601 b 4 are made up of pixels that receive light in the entirewavelength region of visible light.

FIG. 78 illustrates a tenth example of the pixel arrangement of the fourpixel arrays 1601 b 1 to 1601 b 4 included in the light receivingelement 12 of the camera module 1.

In the light receiving element 12 illustrated in FIG. 78, all pixels ofthe pixel array 1601 b 1 are made up of pixels that receive light in theentire wavelength region of visible light. All pixels of the pixel array1601 b 2 are made up of pixels that receive light in the entirewavelength region of visible light. All pixels of the pixel array 1601 b3 are made up of pixels that receive light in the red wavelength. Allpixels of the pixel array 1601 b 4 are made up of pixels that receivelight in the entire wavelength region of visible light.

As illustrated in FIGS. 75 to 78, the pixel arrays 1601 b 1 to 1601 b 4of the light receiving element 12 can be configured so that each of therespective pixel arrays receives light in the same wavelength region.

A known RGB three-plate type solid-state imaging apparatus in relatedart includes three light receiving elements, and the respective lightreceiving elements capture R, G, and B images only, respectively. In theknown RGB three-plate type solid-state imaging apparatus in related art,light incident on one optical unit is split in three directions by aprism and the split light components are received using three lightreceiving elements. Due to this, the positions of the subject imagesincident on the three light receiving elements are the same. Thus, it isdifficult to obtain a highly sensitive image by applying thesuper-resolution technique to these three images.

In contrast, in the camera module illustrated in FIGS. 10A to 10F andFIGS. 11A to 11D, which uses any one of the light receiving elements 12illustrated in FIGS. 75 to 78, two optical units 13 are disposed in eachof the vertical and horizontal directions of the surface of the cameramodule 1 serving as the light incidence surface, and the optical axes ofthese four optical units 13 extend in the same direction in parallel toeach other. Due to this, it is possible to obtain a plurality of imageswhich are not necessarily identical using the four different lightreceiving areas 1601 a 1 to 1601 a 4 included in the light receivingelement 12 with the optical axes extending in the same direction.

The camera module 1 having such a structure provides an effect that itis possible to obtain an image having a higher resolution based on aplurality of images obtained from the four optical units 13 having theabove-described arrangement than that of one image obtained from oneoptical unit 13 by applying the super-resolution technique to theseimages.

The configuration in which four images of the colors G, R, G, and B areobtained by the light receiving element 12 illustrated in FIG. 75provides the same effect as that provided by the configuration of thelight receiving element 12 illustrated in FIG. 66 in which the fourpixels of the colors G, R, G, and B form a repetition unit.

The configuration in which four images of the colors R, G, B, and C areobtained by the light receiving element 12 illustrated in FIG. 76provides the same effect as that provided by the configuration of thelight receiving element 12 illustrated in FIG. 67 in which the fourpixels of the colors R, G, B, and C form a repetition unit.

The configuration in which four images of the colors R, C, B, and C areobtained by the light receiving element 12 illustrated in FIG. 77provides the same effect as that provided by the configuration of thelight receiving element 12 illustrated in FIG. 68 in which the fourpixels of the colors R, C, B, and C form a repetition unit.

The configuration in which four images of the colors R, C, C, and C areobtained by the light receiving element 12 illustrated in FIG. 78provides the same effect as that provided by the configuration of thelight receiving element 12 illustrated in FIG. 69 in which the fourpixels of the colors R, C, C, and C form a repetition unit.

The diaphragm plate 51 of the camera module 1 including any one of thelight receiving elements 12 illustrated in FIGS. 75 to 78 may havevarious configurations of the diaphragm plates 51 illustrated in FIGS.64A to 64D and the modifications thereof.

FIG. 79A illustrates an eleventh example of the pixel arrangement of thefour pixel arrays 1601 b 1 to 1601 b 4 included in the light receivingelement 12 of the camera module 1.

In the light receiving element 12 illustrated in FIG. 79A, the pixelsizes of each pixel of the pixel arrays 1601 b 1 to 1601 b 4 or thewavelengths of light received by each pixel are different.

As for the pixel size, the pixel array 1601 b 1 has the smallest size,the pixel arrays 1601 b 2 and 1601 b 3 have the same size which islarger than the pixel array 1601 b 1, and the pixel array 1601 b 4 has alarger size than the pixel arrays 1601 b 2 and 1601 b 3. The pixel sizeis proportional to the size of the photoelectric conversion unitincluded in each pixel.

As for the wavelength of light received by each pixel, the pixel arrays1601 b 1, 1601 b 2, and 1601 b 4 are made up of pixels that receivelight in the entire wavelength region of visible light, and the pixelarray 1601 b 3 is made up of pixels that receive light in the redwavelength.

The configuration of the light receiving element 12 illustrated in FIG.79A provides an effect that, when the illuminance of a subject is high,and therefore, a large signal is obtained in the light receiving element12, for example, it is possible to obtain images having a highresolution using the light receiving area 1601 a 1 in which the pixelshave a small size.

Moreover, it is possible to provide an effect that, when the illuminanceof a subject is low, and therefore, there is a possibility that the S/Nratio of an image decreases because a large signal is not obtained inthe light receiving element 12, for example, it is possible to obtainimages having a high S/N ratio using the light receiving area 1601 a 2in which an image having a high S/N ratio is obtained.

Further, it is possible to provide an effect that, when the illuminanceof a subject is further lower, and therefore, there is a possibilitythat the S/N ratio of an image decreases further in the light receivingelement 12, for example, it is possible to obtain images having a higherS/N ratio using the light receiving area 1601 a 4 in which images havinga higher S/N ratio are obtained.

The configuration in which the light receiving element 12 illustrated inFIG. 79A is used in combination with the diaphragm plate 51 illustratedin FIG. 79B among the three shapes of the diaphragm plates 51illustrated in FIGS. 79B to 79D provides the same effects as thatprovided by the configuration in which the light receiving element 12illustrated in FIG. 74A is used in combination with the diaphragm plate51 illustrated in FIG. 74B among the three shapes of the diaphragmplates 51 illustrated in FIGS. 74B to 74D.

The configuration in which the light receiving element 12 illustrated inFIG. 79A is used in combination with the diaphragm plate 51 illustratedin FIG. 79C among the three shapes of the diaphragm plates 51illustrated in FIGS. 79B to 79D provides the same effects as thatprovided by the configuration in which the light receiving element 12illustrated in FIG. 74A is used in combination with the diaphragm plate51 illustrated in FIG. 74C among the three shapes of the diaphragmplates 51 illustrated in FIGS. 74B to 74D.

The configuration in which the light receiving element 12 illustrated inFIG. 79A is used in combination with the diaphragm plate 51 illustratedin FIG. 79D among the three shapes of the diaphragm plates 51illustrated in FIGS. 79B to 79D provides the same effects as thatprovided by the configuration in which the light receiving element 12illustrated in FIG. 74A is used in combination with the diaphragm plate51 illustrated in FIG. 74D among the three shapes of the diaphragmplates 51 illustrated in FIGS. 74B to 74D.

The camera module 1 including the light receiving element 12 illustratedin FIG. 79A may have the configuration of the diaphragm plate 51illustrated in FIG. 64A or 64D, the configurations of the diaphragmplates 51 illustrated in FIGS. 79B to 79D, or the modifications thereof.

18. Application Example to Electronic Apparatus

The camera module 1 can be used in such a form of being incorporatedinto an imaging apparatus such as a digital still camera or a videocamera, a mobile terminal device having an imaging function, and anelectronic apparatus which uses a solid-state imaging apparatus in animage capturing unit (photoelectric conversion unit) such as a copyingmachine which uses a solid-state imaging apparatus in an image readingunit.

FIG. 80 is a block diagram illustrating a configuration example of animaging apparatus as an electronic apparatus to which the presenttechnique is applied.

An imaging apparatus 2000 illustrated in FIG. 80 includes a cameramodule 2002 and a digital signal processor (DSP) circuit 2003 which is acamera signal processing circuit. Moreover, the imaging apparatus 2000includes a frame memory 2004, a display unit 2005, a recording unit2006, an operating unit 2007, and a power supply unit 2008. The DSPcircuit 2003, the frame memory 2004, the display unit 2005, therecording unit 2006, the operating unit 2007, the power supply unit 2008are connected to one another via a bus line 2009.

An image sensor 2001 in the camera module 2002 captures incident light(image light) from a subject, converts the amount of the incident lightformed on an imaging surface to an electrical signal in respectivepixels, and outputs the electrical signal as a pixel signal. The cameramodule 1 is used as the camera module 2002, and the image sensor 2001corresponds to the light receiving element 12.

The display unit 2005 is a panel-type display device such as a liquidcrystal panel or an organic electro-luminescence (EL) panel and displaysa moving or still image imaged by the image sensor 2001. The recordingunit 2006 records the moving or still image imaged by the image sensor2001 on a recording medium such as a hard disk or a semiconductormemory.

The operating unit 2007 issues an operation instruction on variousfunctions of the imaging apparatus 2000 according to the operation of auser. The power supply unit 2008 appropriately supplies various types ofpower serving as operation power to the DSP circuit 2003, the framememory 2004, the display unit 2005, the recording unit 2006, and theoperating unit 2007.

As described above, when the camera module 1 on which the stacked lensstructures 11 which are positioned and bonded (stacked) with highaccuracy is used as the camera module 2002, it is possible to improvethe image quality and to reduce the size. Thus, in the imaging apparatus2000 of a camera module for mobile devices such as a video camera, adigital still camera, and a mobile phone, it is possible to reduce thesize of a semiconductor package and to improve the image quality of aphotographed image.

19. Use Example of Image Sensor

The technology according to an embodiment of the present disclosure maybe applied to various products. For example, the technology according toan embodiment of the present disclosure may be applied to an internalinformation acquisition system for a patient, which uses an endoscopiccapsule.

FIG. 81 is a diagram illustrating an example of a schematicconfiguration of an internal information acquisition system 5400 towhich the technology according to an embodiment of the presentdisclosure may be applied. Referring to FIG. 81, the internalinformation acquisition system 5400 includes an endoscopic capsule 5401,and an external control device 5423 that centrally controls theoperation of the internal information acquisition system 5400. Theendoscopic capsule 5401 is swallowed by a patient in an examination. Theendoscopic capsule 5401 has an image capture function and a wirelesscommunication function. The endoscopic capsule 5401 moves through theinterior of organs such as the stomach and the intestines by peristalticmovement or the like until being excreted naturally from the patient,while also successively capturing images (hereinafter also calledinternal images) of the interior of the relevant organs at predeterminedintervals, and successively wirelessly transmitting information aboutthe internal images to the external control device 5423 outside thebody. Based on the received information about the internal images, theexternal control device 5423 generates image data for displaying theinternal images on a display device (not illustrated). In this way, withthe internal information acquisition system 5400, images depicting thepatient's internal conditions can be obtained continually from the timethe endoscopic capsule 5401 is swallowed to the time the endoscopiccapsule 5401 is excreted.

The configurations and functions of the endoscopic capsule 5401 and theexternal control device 5423 will be described in further detail. Asillustrated in FIG. 81, the endoscopic capsule 5401 has the functions ofa light source unit 5405, an image capture unit 5407, an imageprocessing unit 5409, a wireless communication unit 5411, a power supplyunit 5415, a power source unit 5417, a status detection unit 5419, and acontrol unit 5421 built in a capsule-shaped housing 5403.

The light source unit 5405 includes a light source such as alight-emitting diode (LED), for example, and irradiates the imagingfield of the image capture unit 5407 with light.

The image capture unit 5407 includes an image sensor, and an opticalsystem made up of multiple lenses provided in front of the image sensor.Reflected light (hereinafter called observation light) from the lightused to irradiate a body tissue which is the object of observation iscondensed by the optical system and incident on the image sensor. Theimage sensor receives and photoelectrically converts the observationlight to thereby generate an electrical signal corresponding to theobservation light, or in other words, an image signal corresponding tothe observed image. The image signal generated by the image capture unit5407 is provided to the image processing unit 5409. Note that variousknown image sensors such as a complementary metal-oxide-semiconductor(CMOS) image sensor or a charge-coupled device (CCD) image sensor may beused as the image sensor of the image capture unit 5407.

The image processing unit 5409 includes a processor such as a centralprocessing unit (CPU) or a graphics processing unit (GPU), and performsvarious types of signal processing on the image signal generated by theimage capture unit 5407. This signal processing may be a minimal levelof processing (such as image data compression, frame rate conversion,data rate conversion, and/or format conversion, for example) fortransmitting the image signal to the external control device 5423.Configuring the image processing unit 5409 to perform only a minimalnecessary level of processing makes it possible to realize the imageprocessing unit 5409 in a more compact form with lower powerconsumption, which is preferable for the endoscopic capsule 5401.However, if there is extra space or available power inside the housing5403, additional signal processing (such as a noise removal process orother image quality-improving processes, for example) may also beperformed by the image processing unit 5409. The image processing unit5409 provides the image signal subjected to the signal processing to thewireless communication unit 5411 as raw data. Note that if informationabout the status (such as movement or orientation) of the endoscopiccapsule 5401 is acquired by the status detection unit 5419, the imageprocessing unit 5409 may also provide the image signal to the wirelesscommunication unit 5411 in association with the information. This makesit possible to associate the position inside the body where an image iscaptured, the direction in which the image is captured and the like withthe captured image.

The wireless communication unit 5411 includes a communication devicecapable of transmitting and receiving various types of information toand from the external control device 5423. This communication deviceincludes, for example, an antenna 5413 and a processing circuit thatperforms processing such as modulation processing for transmitting andreceiving signals. The wireless communication unit 5411 performspredetermined processing such as modulation processing on the imagesignal that was subjected to the signal processing by the imageprocessing unit 5409, and transmits the image signal to the externalcontrol device 5423 via the antenna 5413. In addition, the wirelesscommunication unit 5411 receives, from the external control device 5423via the antenna 5413, a control signal related to driving control of theendoscopic capsule 5401. The wireless communication unit 5411 providesthe received control signal to the control unit 5421.

The power supply unit 5415 includes, for example, an antenna coil forreceiving power, a power regeneration circuit for regenerating powerfrom a current produced in the antenna coil, and a voltage step-upcircuit. In the power supply unit 5415, the principle of what is calledcontactless or wireless charging is used to generate power.Specifically, an external magnetic field (electromagnetic wave) of apredetermined frequency provided to the antenna coil of the power supplyunit 5415 produces an induced electromotive force in the antenna coil.This electromagnetic wave may be a carrier wave transmitted from theexternal control device 5423 via an antenna 5425, for example. Power isregenerated from the induced electromotive force by the powerregeneration circuit, and the electric potential of the power issuitably adjusted in the voltage step-up circuit, thereby generatingpower for power storage. The power generated by the power supply unit5415 is stored in the power source unit 5417.

The power source unit 5417 includes a secondary battery, and storespower generated by the power supply unit 5415. FIG. 81 omits arrows orthe like indicating the recipients of power from the power source unit5417 for brevity, but power stored in the power source unit 5417 issupplied to the light source unit 5405, the image capture unit 5407, theimage processing unit 5409, the wireless communication unit 5411, thestatus detection unit 5419, and the control unit 5421, and may be usedto drive these components.

The status detection unit 5419 includes a sensor such as an accelerationsensor and/or a gyro sensor for detecting the status of the endoscopiccapsule 5401. The status detection unit 5419 can acquire informationabout the status of the endoscopic capsule 5401 from detection resultsfrom the sensor. The status detection unit 5419 provides the acquiredinformation about the status of the endoscopic capsule 5401 to the imageprocessing unit 5409. As discussed earlier, in the image processing unit5409, the information about the status of the endoscopic capsule 5401may be associated with the image signal.

The control unit 5421 includes a processor such as a CPU, and centrallycontrols the operation of the endoscopic capsule 5401 by operating inaccordance with a predetermined program. The control unit 5421appropriately controls the driving of the light source unit 5405, theimage capture unit 5407, the image processing unit 5409, the wirelesscommunication unit 5411, the power supply unit 5415, the power sourceunit 5417, and the status detection unit 5419 in accordance with acontrol signal transmitted from the external control device 5423,thereby realizing the function of each component as described above.

The external control device 5423 may be a processor such as a CPU orGPU, or a device such as a microcontroller or a control board on which aprocessor and a storage element such as memory are mounted. The externalcontrol device 5423 includes the antenna 5425, and is capable oftransmitting and receiving various types of information to and from theendoscopic capsule 5401 via the antenna 5425. Specifically, the externalcontrol device 5423 controls the operation of the endoscopic capsule5401 by transmitting a control signal to the control unit 5421 of theendoscopic capsule 5401. For example, a light irradiation conditionunder which the light source unit 5405 irradiates a target ofobservation with light may be changed by a control signal from theexternal control device 5423. In addition, an image capture condition(such as the frame rate and the exposure level in the image capture unit5407, for example) may be changed by a control signal from the externalcontrol device 5423. In addition, the content of processing in the imageprocessing unit 5409 and a condition (such as the transmission intervaland the number of images to transmit, for example) under which thewireless communication unit 5411 transmits the image signal may bechanged by a control signal from the external control device 5423.

In addition, the external control device 5423 performs various types ofimage processing on the image signal transmitted from the endoscopiccapsule 5401, and generates image data for displaying a capturedinternal image on a display device. For the image processing, variousknown signal processing, such as a development process (demosaicingprocess), an image quality-improving process (such as a band enhancementprocess, a super-resolution process, a noise reduction (NR) process,and/or a shake correction process), and/or an enlargement process(electronic zoom process), may be performed. The external control device5423 controls the driving of a display device (not illustrated), andcauses the display device to display a captured internal image on thebasis of the generated image data. Alternatively, the external controldevice 5423 may also cause a recording device (not illustrated) torecord the generated image data, or cause a printing device (notillustrated) to make a printout of the generated image data.

The above describes an example of the internal information acquisitionsystem 5400 to which the technology according to an embodiment of thepresent disclosure may be applied. Among the configurations described inthe foregoing, the technology according to an embodiment of the presentdisclosure may be applied favorably to an endoscopic capsule.Specifically, this invention is effective for downsizing an imagingdevice and reducing the burden on patients applying technology accordingto an embodiment of the present.

FIG. 82 is a diagram illustrating a use example of using an image sensorconfigured as the camera module 1.

For example, the image sensor configured as the camera module 1 can beused in various cases of sensing light such as visible light, infraredlight, ultraviolet light, and X-ray in the following manner.

Apparatuses for photographing images provided for viewing, such asdigital cameras, mobile apparatuses with a camera feature.

Apparatuses provided for transportation, such as on-vehicle sensors forphotographing the front, the rear, the surrounding, the interior, andthe like of a vehicle to realize a safe driving function such as anautomated stop function and to recognize the driver's condition,monitoring cameras for monitoring traveling vehicles and roads, anddistance-measuring sensors for measuring the distance between vehicles.

Apparatuses provided for consumer electronics such as TVs,refrigerators, and air-conditioners to photograph the gesture of a userto operate apparatuses according to the gesture.

Apparatuses provided for medical and health-care purposes such asendoscopes and apparatuses for photographing blood vessels usinginfrared light.

Apparatuses provided for security purposes such as anti-crimesurveillance cameras and cameras for personal authentication.

Apparatuses provided for cosmetic purposes such as skin meters forphotographing the skin and microscopes for photographing the scalp.

Apparatus provided for sports purpose such as action cameras dedicatedfor sports and wearable cameras.

Apparatuses provided for agricultural purposes such as cameras formonitoring the conditions of farms and crops.

The embodiment of the present technique is not limited to theabove-described embodiments but various changes can be made withoutdeparting from the spirit of the present technique.

For example, the present technique is not limited to application to asolid-state imaging apparatus that detects a distribution of incidentlight intensity of visible light to photograph the distribution as animage. However, the present technique can be applied to a solid-stateimaging apparatus that photographs a distribution of incident intensityof infrared light, X-ray, or particles as an image and an overallsolid-state imaging apparatus (physical quantity detection device) suchas a finger print detection sensor that detects a distribution otherphysical quantities such as pressure or electrostatic capacitance tophotograph the distribution as an image in a broader sense of meaning.

For example, an embodiment in which all or parts of the plurality ofembodiments described above are combined may be employed.

The advantages described in the present specification are examples onlyand other advantages other than those described in the presentspecification may be provided.

The present technique can have the following configurations.

(1)

A stacked lens structure in which substrates with lenses having a lensdisposed on an inner side of a through-hole formed in the substrate arebonded and stacked by direct bonding.

(2)

The stacked lens structure according to (1), wherein an anti-reflectionfilm is formed on a bonding surface of the substrates with lenses.

(3)

The stacked lens structure according to (2), wherein the anti-reflectionfilm is the same as an anti-reflection film formed on a surface of thelens.

(4)

The stacked lens structure according to (2) or (3), wherein

the anti-reflection film is made up of a plurality of films havingdifferent refractive indices.(5)

The stacked lens structure according to (4), wherein the plurality offilms includes at least a low refractive index film having a firstrefractive index and a high refractive index film having a secondrefractive index, and

a film on a top layer of the anti-reflection film is the low refractiveindex film.(6)

The stacked lens structure according to any one of (1) to (5), wherein

the direct bonding is plasma bonding.(7)

The stacked lens structure according to any one of (1) to (6), wherein

a light blocking film is formed on a side wall of the through-hole.(8)

The stacked lens structure according to any one of (1) to (7), furtherincluding:

a cover glass that protects the lens, whereina light blocking film that functions as an optical diaphragm is formedon the cover glass.(9)

The stacked lens structure according to any one of (1) to (7), wherein

a hole diameter of the through-hole of one of a plurality of the stackedsubstrates with lenses functions as an optical diaphragm.(10)

The stacked lens structure according to any one of (1) to (7), wherein

a plurality of the substrates with lenses and a substrate in which alens is not formed in the through-hole are stacked, and a hole diameterof the through-hole of the substrate in which the lens is not formedfunctions as an optical diaphragm.(11)

The stacked lens structure according to any one of (9) and (10), wherein

a hole diameter of the through-hole that functions as the opticaldiaphragm is smaller than a diameter of a curved surface portion of aplurality of lenses that form the stacked lens structure.(12)

The stacked lens structure according to any one of (9) to (11), wherein

a hole diameter of the through-hole that functions as the opticaldiaphragm is disposed at a position away from a top layer of a pluralityof lenses that form the stacked lens structure in an opposite directionfrom a light incidence direction.(13)

The stacked lens structure according to any one of (9) to (11), wherein

the substrates with lenses are bonded and stacked by metal bonding.(14)

The stacked lens structure according to any one of (1) to (13), wherein

the substrate is a highly-doped substrate in which ions of apredetermined element are doped.(15)

The stacked lens structure according to (14), wherein the substrate isdivided into two regions having different impurity concentrations.

(16)

The stacked lens structure according to any one of (1) to (15), wherein

a side wall of the through-hole has a stair shape.(17)

The stacked lens structure according to (16), wherein a width in a planedirection of the stair shape is between 400 nm and 1 μm.

(18)

The stacked lens structure according to (16) or (17), wherein

the through-hole is formed by repeatedly performing removal of a maskand etching a plurality of number of times.(19)

The stacked lens structure according to (18), wherein the etchingincludes forming a protective film for protecting a side wall of a maskand performing dry-etching.

(20)

A method of manufacturing stacked lens structures, including:

bonding and stacking substrates with lenses having a lens disposed on aninner side of a through-hole formed in the substrate by direct bonding.(21)

An electronic apparatus including:

a camera module including a stacked lens structure in which substrateswith lenses having a lens disposed on an inner side of a through-holeformed in the substrate are bonded and stacked by direct bonding.(22)

A stacked lens structure in which:

at least three substrates with lenses including first to thirdsubstrates with lenses which are substrates with lenses in which athrough-hole is formed in the substrate and a lens is formed on an innerside of the through-hole are stacked,the second substrate with lenses is disposed above the first substratewith lenses,the third substrate with lenses is disposed below the first substratewith lenses,the second substrate with lenses has a different thickness from thethird substrate with lenses, and in a substrate having a smallerthickness among the second and third substrates with lenses, a diameterof the through-hole decreases toward the first substrate with lenses,and the first and second substrates with lenses are bonded by directbonding and the first and third substrates with lenses are bonded bydirect bonding.(23)

A stacked lens structure in which:

at least three substrates with lenses including first to thirdsubstrates with lenses which are substrates with lenses in which athrough-hole is formed in the substrate and a lens is formed on an innerside of the through-hole are stacked,the second substrate with lenses is disposed above the first substratewith lenses,the third substrate with lenses is disposed below the first substratewith lenses,the lens in the second substrate with lenses has a different thicknessfrom the lens in the third substrate with lenses, andin a substrate in which the lens formed on the inner side of thethrough-hole has a smaller volume among the second and third substrateswith lenses, a diameter of the through-hole decreases toward the firstsubstrate with lenses, and the first and second substrates with lensesare bonded by direct bonding and the first and third substrates withlenses are bonded by direct bonding.(24)

A stacked lens structure comprising:

a plurality of substrates including a first substrate having a firstthrough-hole and a second substrate having a second-through hole; anda plurality of lenses including a first lens disposed in the firstthrough-hole and a second lens disposed in the second through-hole,wherein, the first substrate is directly bonded to the second substrate.(25)

The stacked lens structure according to (24), wherein a first layer isformed on the first substrate and a second layer is formed on the secondsubstrate, and each of the first and second layers include one or moreof an oxide, nitride material, or carbon.

(26)

The stacked lens structure according to (25), wherein the firstsubstrate is directly bonded to the second substrate via the first layerand the second layer.

(27)

The stacked lens structure according to (26), wherein the first layerand the second layer include a plasma bonded portion.

(28)

The stacked lens structure according to any one of (24) to (27), whereinan anti-reflection film is formed on a bonding surface of at least oneof the substrates of the plurality of substrates.

(29)

The stacked lens structure according to (28), wherein theanti-reflection film is formed on a surface of at least one of thelenses of the plurality of lenses.

(30)

The stacked lens structure according to (28), wherein theanti-reflection film includes a plurality of films having differentrefractive indices.

(31)

The stacked lens structure according to (30), wherein the plurality offilms includes at least a low refractive index film having a firstrefractive index and a high refractive index film having a secondrefractive index, and a film at a top layer of the anti-reflection filmis the low refractive index film.

(32)

The stacked lens structure according to any one of (24) to (31), whereina light-blocking film is formed on a side wall of at least one of thefirst and second through-holes.

(33)

The stacked lens structure according to any one of (24) to (32), furthercomprising: a cover glass including an optical diaphragm formed thereon,wherein the optical diaphragm includes an aperture formed in alight-blocking film.

(34)

The stacked lens structure according to any one of (24) to (33), whereinan optical diaphragm based on a diameter of the through-hole formed inat least one of the substrates of the plurality of substrates reduces anamount of light that passes through the at least one of the substrates.

(35)

The stacked lens structure according to any one of (24) to (34), whereina substrate including a through-hole without a lens and at least one ofthe first substrate or the second substrate are stacked, and an opticaldiaphragm based on a diameter of the through-hole without the lenscontrols an amount of light that passes through the through-hole withoutthe lens.

(36)

The stacked lens structure according to (35), wherein the diameter ofthe through-hole without the lens is smaller than a diameter of a curvedsurface portion of at least one of the lenses of the plurality oflenses.

(37)

The stacked lens structure according to (35), wherein the diameter ofthe through-hole without the lens is disposed on an uppermost layer ofthe substrate of the plurality of substrates that form the stacked lensstructure.

(38)

The stacked lens structure according to any one of (24) to (37), whereinat least one of the substrates of the plurality of substrates is dividedinto two regions having different impurity concentrations.

(39)

The stacked lens structure according to any one of (24) to (38), whereina side wall of at least one of the through-holes of the first and secondthrough-holes includes a stair shape.

(40)

The stacked lens structure according to any one of (24) to (39), whereina width of the stair shape is between 400 nm and 1 μm.

(41)

The stacked lens structure according to any one of (24) to (40), furthercomprising: a third substrate having a third through-hole and a thirdlens disposed therein, wherein, the second substrate is disposed abovethe first substrate, the third substrate is disposed below the firstsubstrate, at least one of (i) a thickness of the second substrate isdifferent from a thickness of the third substrate, or (ii) a thicknessof the second lens in the second substrate is different from a thicknessof the third lens in the third substrate, and the first and secondsubstrates are directly bonded and the first and third substrates aredirectly bonded.

(42)

A method of manufacturing a stacked lens structure, the methodcomprising: forming a first substrate including a first through-holewith a first lens disposed therein; forming a second substrate includinga second through-hole with a second lens disposed therein, wherein thefirst substrate is directly bonded to the second substrate.

(43)

An electronic apparatus comprising:

a camera module including a stacked lens structure including: aplurality of substrates including a first substrate having a firstthrough-hole and a second substrate having a second-through hole; and aplurality of lenses including a first lens disposed in the firstthrough-hole and a second lens disposed in the second through-hole,wherein, the first substrate is directly bonded to the second substrate.

REFERENCE SIGNS LIST

-   1 Camera module-   11 Stacked lens structure-   12 Light receiving element-   13 Optical unit-   21 Lens-   41 (41 a to 41 g) Substrate with lenses-   43 Sensor substrate-   51 Diaphragm plate-   52 Opening-   81 Support substrate-   82 Lens resin portion-   83 Through-hole-   121 Light blocking film-   122 Upper surface layer-   123 Lower surface layer-   141 Etching mask-   142 Protective film-   1501 cover glass-   1502 light blocking film-   1503 opening-   1511, 1512 substrate-   1531 substrate with lenses-   1542 metal film-   1551 first region-   1552 second region-   1561W highly-doped substrate-   2000 imaging apparatus-   2001 image sensor-   2002 camera module

1-20. (canceled)
 21. A stacked lens structure comprising: a plurality ofsubstrates including a first substrate having a first through-hole, asecond substrate having a second through-hole, and a third substratehaving a third through-hole; and a plurality of lenses including a firstlens disposed in the first through-hole, a second lens disposed in thesecond through-hole, and a third lens disposed in the thirdthrough-hole; wherein, the first substrate is bonded to the secondsubstrate to form a first bonding surface, the second substrate isbonded to the third substrate to form a second bonding surface, and afirst distance from a central line to the first bonding surface isdifferent than a second distance from the central line to the secondbonding surface, the central line passing through a central point of thestacked lens structure and running in a plane direction of the first tothird substrates, the central point being a center of the stacked lensstructure in a thickness direction of the stacked lens structure. 22.The stacked lens structure according to claim 21, wherein the firstsubstrate is bonded to the second substrate via a first insulatinglayer.
 23. The stacked lens structure according to claim 22, wherein thesecond substrate is bonded to the third substrate via a secondinsulating layer.
 24. The stacked lens structure according to claim 23,wherein the first insulating layer and the second insulating layerinclude a plasma bonded portion.
 25. The stacked lens structureaccording to claim 21, wherein an anti-reflection film is formed on atleast one of the substrates of the plurality of substrates.
 26. Thestacked lens structure according to claim 25, wherein theanti-reflection film is formed on a surface of at least one of thelenses of the plurality of lenses.
 27. The stacked lens structureaccording to claim 25, wherein the anti-reflection film includes aplurality of films having different refractive indices.
 28. The stackedlens structure according to claim 27, wherein the plurality of filmsincludes at least a low refractive index film having a first refractiveindex and a high refractive index film having a second refractive index,and a film at a top layer of the anti-reflection film is the lowrefractive index film.
 29. The stacked lens structure according to claim21, wherein a light-blocking film is formed on a side wall of at leastone of the first and second through-holes.
 30. The stacked lensstructure according to claim 21, further comprising: a cover glassincluding an optical diaphragm formed thereon, wherein the opticaldiaphragm includes an aperture formed in a light-blocking film.
 31. Thestacked lens structure according to claim 21, wherein, the secondsubstrate is disposed above the first substrate, the third substrate isdisposed below the first substrate, and at least one of (i) a thicknessof the second substrate is different from a thickness of the thirdsubstrate, or (ii) a thickness of the second lens in the secondsubstrate is different from a thickness of the third lens in the thirdsubstrate.
 32. A camera module comprising: a light receiving element;and a stacked lens structure including: a plurality of substratesincluding a first substrate having a first through-hole, a secondsubstrate having a second through-hole, and a third substrate having athird through-hole; and a plurality of lenses including a first lensdisposed in the first through-hole, a second lens disposed in the secondthrough-hole, and a third lens disposed in the third through-hole;wherein, the first substrate is bonded to the second substrate to form afirst bonding surface, the second substrate is bonded to the thirdsubstrate to form a second bonding surface, and a first distance from acentral line to the first bonding surface is different than a seconddistance from the central line to the second bonding surface, thecentral line passing through a central point of the stacked lensstructure and running in a plane direction of the first to thirdsubstrates, the central point being a center of the stacked lensstructure in a thickness direction of the stacked lens structure. 33.The camera module according to claim 32, wherein the stacked lensstructure is fixed on an upper side of the light receiving element via astructure material.
 34. The camera module according to claim 32, furthercomprising: a first structure material disposed in a portion of an upperside of the light receiving element; a light transmitting substrate overthe light receiving element and fixed to the light receiving element bythe first structure material; a second structure material disposed on anupper side of the light transmitting substrate, wherein the stacked lensstructure is over the light transmitting substrate and is fixed to thelight transmitting substrate by the second structure material.
 35. Thecamera module according to claim 32, further comprising: a resin layerdisposed on an entire upper surface of the light receiving element; alight transmitting substrate over the light receiving element and fixedto the light receiving element by the resin layer; a structure materialdisposed on an upper side of the light transmitting substrate, whereinthe stacked lens structure is over the light transmitting substrate andis fixed to the light transmitting substrate by the structure material.36. The camera module according to claim 32, further comprising: amechanism to move the stacked lens structure and to adjust a distancefrom the stacked lens structure to an imaging surface of the lightreceiving element.
 37. The camera module according to claim 32, whereinthe first substrate includes a plurality of first through-holes, aplurality of first lenses being disposed respectively therein, whereinthe second substrate includes a plurality of second through-holes, aplurality of second lenses being disposed respectively therein, whereinthe third substrate includes a plurality of third through-holes, aplurality of third lenses being disposed respectively therein, whereinthe stacked lens structure includes optical units, wherein each of theoptical units is configured to include a plurality of lenses in oneoptical axis direction of each optical unit, and wherein each of theoptical units is configured to include an optical diaphragm.
 38. Thecamera module according to claim 37, wherein a first diameter of a firstoptical diaphragm in a first optical unit is different from a seconddiameter of a first optical diaphragm in another optical unit.
 39. Thecamera module according to claim 37, wherein a first diameter of a lensin a first optical unit of one of the first to third substrates isdifferent from a second diameter of a lens in another optical unit in asame one of the first to third substrates.
 40. The camera moduleaccording to claim 37, wherein a number of lenses in a first opticalunit is different from a number of lenses in another optical unit.